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* [PATCH v22 1/2] Split vacuumdb to create vacuuming.c/h
@ 2025-09-25 12:58 Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Álvaro Herrera @ 2025-09-25 12:58 UTC (permalink / raw)
This allows these routines to be reused by a future utility heavily
based on vacuumdb.
Discussion: https://postgr.es/m/[email protected]
---
src/bin/scripts/Makefile | 4 +-
src/bin/scripts/meson.build | 28 +-
src/bin/scripts/vacuumdb.c | 1055 +----------------------------------
src/bin/scripts/vacuuming.c | 1012 +++++++++++++++++++++++++++++++++
src/bin/scripts/vacuuming.h | 68 +++
5 files changed, 1131 insertions(+), 1036 deletions(-)
create mode 100644 src/bin/scripts/vacuuming.c
create mode 100644 src/bin/scripts/vacuuming.h
diff --git a/src/bin/scripts/Makefile b/src/bin/scripts/Makefile
index f6b4d40810b..019ca06455d 100644
--- a/src/bin/scripts/Makefile
+++ b/src/bin/scripts/Makefile
@@ -28,7 +28,7 @@ createuser: createuser.o common.o $(WIN32RES) | submake-libpq submake-libpgport
dropdb: dropdb.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
dropuser: dropuser.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
clusterdb: clusterdb.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
-vacuumdb: vacuumdb.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
+vacuumdb: vacuumdb.o vacuuming.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
reindexdb: reindexdb.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
pg_isready: pg_isready.o common.o $(WIN32RES) | submake-libpq submake-libpgport submake-libpgfeutils
@@ -50,7 +50,7 @@ uninstall:
clean distclean:
rm -f $(addsuffix $(X), $(PROGRAMS)) $(addsuffix .o, $(PROGRAMS))
- rm -f common.o $(WIN32RES)
+ rm -f common.o vacuuming.o $(WIN32RES)
rm -rf tmp_check
export with_icu
diff --git a/src/bin/scripts/meson.build b/src/bin/scripts/meson.build
index 80df7c33257..a4fed59d1c9 100644
--- a/src/bin/scripts/meson.build
+++ b/src/bin/scripts/meson.build
@@ -12,7 +12,6 @@ binaries = [
'createuser',
'dropuser',
'clusterdb',
- 'vacuumdb',
'reindexdb',
'pg_isready',
]
@@ -35,6 +34,33 @@ foreach binary : binaries
bin_targets += binary
endforeach
+vacuuming_common = static_library('libvacuuming_common',
+ files('common.c', 'vacuuming.c'),
+ dependencies: [frontend_code, libpq],
+ kwargs: internal_lib_args,
+)
+
+binaries = [
+ 'vacuumdb',
+]
+foreach binary : binaries
+ binary_sources = files('@[email protected]'.format(binary))
+
+ if host_system == 'windows'
+ binary_sources += rc_bin_gen.process(win32ver_rc, extra_args: [
+ '--NAME', binary,
+ '--FILEDESC', '@0@ - PostgreSQL utility'.format(binary),])
+ endif
+
+ binary = executable(binary,
+ binary_sources,
+ link_with: [vacuuming_common],
+ dependencies: [frontend_code, libpq],
+ kwargs: default_bin_args,
+ )
+ bin_targets += binary
+endforeach
+
tests += {
'name': 'scripts',
'sd': meson.current_source_dir(),
diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c
index 6e30f223efe..00babc5c9c0 100644
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -14,91 +14,13 @@
#include <limits.h>
-#include "catalog/pg_attribute_d.h"
-#include "catalog/pg_class_d.h"
#include "common.h"
-#include "common/connect.h"
#include "common/logging.h"
-#include "fe_utils/cancel.h"
#include "fe_utils/option_utils.h"
-#include "fe_utils/parallel_slot.h"
-#include "fe_utils/query_utils.h"
-#include "fe_utils/simple_list.h"
-#include "fe_utils/string_utils.h"
-
-
-/* vacuum options controlled by user flags */
-typedef struct vacuumingOptions
-{
- bool analyze_only;
- bool verbose;
- bool and_analyze;
- bool full;
- bool freeze;
- bool disable_page_skipping;
- bool skip_locked;
- int min_xid_age;
- int min_mxid_age;
- int parallel_workers; /* >= 0 indicates user specified the
- * parallel degree, otherwise -1 */
- bool no_index_cleanup;
- bool force_index_cleanup;
- bool do_truncate;
- bool process_main;
- bool process_toast;
- bool skip_database_stats;
- char *buffer_usage_limit;
- bool missing_stats_only;
-} vacuumingOptions;
-
-/* object filter options */
-typedef enum
-{
- OBJFILTER_NONE = 0, /* no filter used */
- OBJFILTER_ALL_DBS = (1 << 0), /* -a | --all */
- OBJFILTER_DATABASE = (1 << 1), /* -d | --dbname */
- OBJFILTER_TABLE = (1 << 2), /* -t | --table */
- OBJFILTER_SCHEMA = (1 << 3), /* -n | --schema */
- OBJFILTER_SCHEMA_EXCLUDE = (1 << 4), /* -N | --exclude-schema */
-} VacObjFilter;
-
-static VacObjFilter objfilter = OBJFILTER_NONE;
-
-static SimpleStringList *retrieve_objects(PGconn *conn,
- vacuumingOptions *vacopts,
- SimpleStringList *objects,
- bool echo);
-
-static void vacuum_one_database(ConnParams *cparams,
- vacuumingOptions *vacopts,
- int stage,
- SimpleStringList *objects,
- SimpleStringList **found_objs,
- int concurrentCons,
- const char *progname, bool echo, bool quiet);
-
-static void vacuum_all_databases(ConnParams *cparams,
- vacuumingOptions *vacopts,
- bool analyze_in_stages,
- SimpleStringList *objects,
- int concurrentCons,
- const char *progname, bool echo, bool quiet);
-
-static void prepare_vacuum_command(PQExpBuffer sql, int serverVersion,
- vacuumingOptions *vacopts, const char *table);
-
-static void run_vacuum_command(PGconn *conn, const char *sql, bool echo,
- const char *table);
+#include "vacuuming.h"
static void help(const char *progname);
-
-void check_objfilter(void);
-
-static char *escape_quotes(const char *src);
-
-/* For analyze-in-stages mode */
-#define ANALYZE_NO_STAGE -1
-#define ANALYZE_NUM_STAGES 3
+static void check_objfilter(VacObjFilter objfilter);
int
@@ -145,18 +67,16 @@ main(int argc, char *argv[])
int c;
const char *dbname = NULL;
const char *maintenance_db = NULL;
- char *host = NULL;
- char *port = NULL;
- char *username = NULL;
- enum trivalue prompt_password = TRI_DEFAULT;
ConnParams cparams;
bool echo = false;
bool quiet = false;
vacuumingOptions vacopts;
bool analyze_in_stages = false;
SimpleStringList objects = {NULL, NULL};
+ VacObjFilter objfilter = OBJFILTER_NONE;
int concurrentCons = 1;
int tbl_count = 0;
+ int ret;
/* initialize options */
memset(&vacopts, 0, sizeof(vacopts));
@@ -168,13 +88,18 @@ main(int argc, char *argv[])
vacopts.process_main = true;
vacopts.process_toast = true;
+ /* the same for connection parameters */
+ memset(&cparams, 0, sizeof(cparams));
+ cparams.prompt_password = TRI_DEFAULT;
+
pg_logging_init(argv[0]);
progname = get_progname(argv[0]);
set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pgscripts"));
handle_help_version_opts(argc, argv, "vacuumdb", help);
- while ((c = getopt_long(argc, argv, "ad:efFh:j:n:N:p:P:qt:U:vwWzZ", long_options, &optindex)) != -1)
+ while ((c = getopt_long(argc, argv, "ad:efFh:j:n:N:p:P:qt:U:vwWzZ",
+ long_options, &optindex)) != -1)
{
switch (c)
{
@@ -195,7 +120,7 @@ main(int argc, char *argv[])
vacopts.freeze = true;
break;
case 'h':
- host = pg_strdup(optarg);
+ cparams.pghost = pg_strdup(optarg);
break;
case 'j':
if (!option_parse_int(optarg, "-j/--jobs", 1, INT_MAX,
@@ -211,7 +136,7 @@ main(int argc, char *argv[])
simple_string_list_append(&objects, optarg);
break;
case 'p':
- port = pg_strdup(optarg);
+ cparams.pgport = pg_strdup(optarg);
break;
case 'P':
if (!option_parse_int(optarg, "-P/--parallel", 0, INT_MAX,
@@ -227,16 +152,16 @@ main(int argc, char *argv[])
tbl_count++;
break;
case 'U':
- username = pg_strdup(optarg);
+ cparams.pguser = pg_strdup(optarg);
break;
case 'v':
vacopts.verbose = true;
break;
case 'w':
- prompt_password = TRI_NO;
+ cparams.prompt_password = TRI_NO;
break;
case 'W':
- prompt_password = TRI_YES;
+ cparams.prompt_password = TRI_YES;
break;
case 'z':
vacopts.and_analyze = true;
@@ -317,7 +242,7 @@ main(int argc, char *argv[])
* Validate the combination of filters specified in the command-line
* options.
*/
- check_objfilter();
+ check_objfilter(objfilter);
if (vacopts.analyze_only)
{
@@ -380,74 +305,18 @@ main(int argc, char *argv[])
pg_fatal("cannot use the \"%s\" option without \"%s\" or \"%s\"",
"missing-stats-only", "analyze-only", "analyze-in-stages");
- /* fill cparams except for dbname, which is set below */
- cparams.pghost = host;
- cparams.pgport = port;
- cparams.pguser = username;
- cparams.prompt_password = prompt_password;
- cparams.override_dbname = NULL;
-
- setup_cancel_handler(NULL);
-
- /* Avoid opening extra connections. */
- if (tbl_count && (concurrentCons > tbl_count))
- concurrentCons = tbl_count;
-
- if (objfilter & OBJFILTER_ALL_DBS)
- {
- cparams.dbname = maintenance_db;
-
- vacuum_all_databases(&cparams, &vacopts,
- analyze_in_stages,
- &objects,
- concurrentCons,
- progname, echo, quiet);
- }
- else
- {
- if (dbname == NULL)
- {
- if (getenv("PGDATABASE"))
- dbname = getenv("PGDATABASE");
- else if (getenv("PGUSER"))
- dbname = getenv("PGUSER");
- else
- dbname = get_user_name_or_exit(progname);
- }
-
- cparams.dbname = dbname;
-
- if (analyze_in_stages)
- {
- int stage;
- SimpleStringList *found_objs = NULL;
-
- for (stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
- {
- vacuum_one_database(&cparams, &vacopts,
- stage,
- &objects,
- vacopts.missing_stats_only ? &found_objs : NULL,
- concurrentCons,
- progname, echo, quiet);
- }
- }
- else
- vacuum_one_database(&cparams, &vacopts,
- ANALYZE_NO_STAGE,
- &objects, NULL,
- concurrentCons,
- progname, echo, quiet);
- }
-
- exit(0);
+ ret = vacuuming_main(&cparams, dbname, maintenance_db, &vacopts,
+ objfilter, &objects, tbl_count, analyze_in_stages,
+ concurrentCons,
+ progname, echo, quiet);
+ exit(ret);
}
/*
* Verify that the filters used at command line are compatible.
*/
void
-check_objfilter(void)
+check_objfilter(VacObjFilter objfilter)
{
if ((objfilter & OBJFILTER_ALL_DBS) &&
(objfilter & OBJFILTER_DATABASE))
@@ -466,886 +335,6 @@ check_objfilter(void)
pg_fatal("cannot vacuum all tables in schema(s) and exclude schema(s) at the same time");
}
-/*
- * Returns a newly malloc'd version of 'src' with escaped single quotes and
- * backslashes.
- */
-static char *
-escape_quotes(const char *src)
-{
- char *result = escape_single_quotes_ascii(src);
-
- if (!result)
- pg_fatal("out of memory");
- return result;
-}
-
-/*
- * vacuum_one_database
- *
- * Process tables in the given database.
- *
- * There are two ways to specify the list of objects to process:
- *
- * 1) The "found_objs" parameter is a double pointer to a fully qualified list
- * of objects to process, as returned by a previous call to
- * vacuum_one_database().
- *
- * a) If both "found_objs" (the double pointer) and "*found_objs" (the
- * once-dereferenced double pointer) are not NULL, this list takes
- * priority, and anything specified in "objects" is ignored.
- *
- * b) If "found_objs" (the double pointer) is not NULL but "*found_objs"
- * (the once-dereferenced double pointer) _is_ NULL, the "objects"
- * parameter takes priority, and the results of the catalog query
- * described in (2) are stored in "found_objs".
- *
- * c) If "found_objs" (the double pointer) is NULL, the "objects"
- * parameter again takes priority, and the results of the catalog query
- * are not saved.
- *
- * 2) The "objects" parameter is a user-specified list of objects to process.
- * When (1b) or (1c) applies, this function performs a catalog query to
- * retrieve a fully qualified list of objects to process, as described
- * below.
- *
- * a) If "objects" is not NULL, the catalog query gathers only the objects
- * listed in "objects".
- *
- * b) If "objects" is NULL, all tables in the database are gathered.
- *
- * Note that this function is only concerned with running exactly one stage
- * when in analyze-in-stages mode; caller must iterate on us if necessary.
- *
- * If concurrentCons is > 1, multiple connections are used to vacuum tables
- * in parallel.
- */
-static void
-vacuum_one_database(ConnParams *cparams,
- vacuumingOptions *vacopts,
- int stage,
- SimpleStringList *objects,
- SimpleStringList **found_objs,
- int concurrentCons,
- const char *progname, bool echo, bool quiet)
-{
- PQExpBufferData sql;
- PGconn *conn;
- SimpleStringListCell *cell;
- ParallelSlotArray *sa;
- int ntups = 0;
- bool failed = false;
- const char *initcmd;
- SimpleStringList *ret = NULL;
- const char *stage_commands[] = {
- "SET default_statistics_target=1; SET vacuum_cost_delay=0;",
- "SET default_statistics_target=10; RESET vacuum_cost_delay;",
- "RESET default_statistics_target;"
- };
- const char *stage_messages[] = {
- gettext_noop("Generating minimal optimizer statistics (1 target)"),
- gettext_noop("Generating medium optimizer statistics (10 targets)"),
- gettext_noop("Generating default (full) optimizer statistics")
- };
-
- Assert(stage == ANALYZE_NO_STAGE ||
- (stage >= 0 && stage < ANALYZE_NUM_STAGES));
-
- conn = connectDatabase(cparams, progname, echo, false, true);
-
- if (vacopts->disable_page_skipping && PQserverVersion(conn) < 90600)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "disable-page-skipping", "9.6");
- }
-
- if (vacopts->no_index_cleanup && PQserverVersion(conn) < 120000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "no-index-cleanup", "12");
- }
-
- if (vacopts->force_index_cleanup && PQserverVersion(conn) < 120000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "force-index-cleanup", "12");
- }
-
- if (!vacopts->do_truncate && PQserverVersion(conn) < 120000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "no-truncate", "12");
- }
-
- if (!vacopts->process_main && PQserverVersion(conn) < 160000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "no-process-main", "16");
- }
-
- if (!vacopts->process_toast && PQserverVersion(conn) < 140000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "no-process-toast", "14");
- }
-
- if (vacopts->skip_locked && PQserverVersion(conn) < 120000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "skip-locked", "12");
- }
-
- if (vacopts->min_xid_age != 0 && PQserverVersion(conn) < 90600)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "--min-xid-age", "9.6");
- }
-
- if (vacopts->min_mxid_age != 0 && PQserverVersion(conn) < 90600)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "--min-mxid-age", "9.6");
- }
-
- if (vacopts->parallel_workers >= 0 && PQserverVersion(conn) < 130000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "--parallel", "13");
- }
-
- if (vacopts->buffer_usage_limit && PQserverVersion(conn) < 160000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "--buffer-usage-limit", "16");
- }
-
- if (vacopts->missing_stats_only && PQserverVersion(conn) < 150000)
- {
- PQfinish(conn);
- pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
- "--missing-stats-only", "15");
- }
-
- /* skip_database_stats is used automatically if server supports it */
- vacopts->skip_database_stats = (PQserverVersion(conn) >= 160000);
-
- if (!quiet)
- {
- if (stage != ANALYZE_NO_STAGE)
- printf(_("%s: processing database \"%s\": %s\n"),
- progname, PQdb(conn), _(stage_messages[stage]));
- else
- printf(_("%s: vacuuming database \"%s\"\n"),
- progname, PQdb(conn));
- fflush(stdout);
- }
-
- /*
- * If the caller provided the results of a previous catalog query, just
- * use that. Otherwise, run the catalog query ourselves and set the
- * return variable if provided.
- */
- if (found_objs && *found_objs)
- ret = *found_objs;
- else
- {
- ret = retrieve_objects(conn, vacopts, objects, echo);
- if (found_objs)
- *found_objs = ret;
- }
-
- /*
- * Count the number of objects in the catalog query result. If there are
- * none, we are done.
- */
- for (cell = ret ? ret->head : NULL; cell; cell = cell->next)
- ntups++;
-
- if (ntups == 0)
- {
- PQfinish(conn);
- return;
- }
-
- /*
- * Ensure concurrentCons is sane. If there are more connections than
- * vacuumable relations, we don't need to use them all.
- */
- if (concurrentCons > ntups)
- concurrentCons = ntups;
- if (concurrentCons <= 0)
- concurrentCons = 1;
-
- /*
- * All slots need to be prepared to run the appropriate analyze stage, if
- * caller requested that mode. We have to prepare the initial connection
- * ourselves before setting up the slots.
- */
- if (stage == ANALYZE_NO_STAGE)
- initcmd = NULL;
- else
- {
- initcmd = stage_commands[stage];
- executeCommand(conn, initcmd, echo);
- }
-
- /*
- * Setup the database connections. We reuse the connection we already have
- * for the first slot. If not in parallel mode, the first slot in the
- * array contains the connection.
- */
- sa = ParallelSlotsSetup(concurrentCons, cparams, progname, echo, initcmd);
- ParallelSlotsAdoptConn(sa, conn);
-
- initPQExpBuffer(&sql);
-
- cell = ret->head;
- do
- {
- const char *tabname = cell->val;
- ParallelSlot *free_slot;
-
- if (CancelRequested)
- {
- failed = true;
- goto finish;
- }
-
- free_slot = ParallelSlotsGetIdle(sa, NULL);
- if (!free_slot)
- {
- failed = true;
- goto finish;
- }
-
- prepare_vacuum_command(&sql, PQserverVersion(free_slot->connection),
- vacopts, tabname);
-
- /*
- * Execute the vacuum. All errors are handled in processQueryResult
- * through ParallelSlotsGetIdle.
- */
- ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
- run_vacuum_command(free_slot->connection, sql.data,
- echo, tabname);
-
- cell = cell->next;
- } while (cell != NULL);
-
- if (!ParallelSlotsWaitCompletion(sa))
- {
- failed = true;
- goto finish;
- }
-
- /* If we used SKIP_DATABASE_STATS, mop up with ONLY_DATABASE_STATS */
- if (vacopts->skip_database_stats && stage == ANALYZE_NO_STAGE &&
- !vacopts->analyze_only)
- {
- const char *cmd = "VACUUM (ONLY_DATABASE_STATS);";
- ParallelSlot *free_slot = ParallelSlotsGetIdle(sa, NULL);
-
- if (!free_slot)
- {
- failed = true;
- goto finish;
- }
-
- ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
- run_vacuum_command(free_slot->connection, cmd, echo, NULL);
-
- if (!ParallelSlotsWaitCompletion(sa))
- failed = true;
- }
-
-finish:
- ParallelSlotsTerminate(sa);
- pg_free(sa);
-
- termPQExpBuffer(&sql);
-
- if (failed)
- exit(1);
-}
-
-/*
- * Prepare the list of tables to process by querying the catalogs.
- *
- * Since we execute the constructed query with the default search_path (which
- * could be unsafe), everything in this query MUST be fully qualified.
- *
- * First, build a WITH clause for the catalog query if any tables were
- * specified, with a set of values made of relation names and their optional
- * set of columns. This is used to match any provided column lists with the
- * generated qualified identifiers and to filter for the tables provided via
- * --table. If a listed table does not exist, the catalog query will fail.
- */
-static SimpleStringList *
-retrieve_objects(PGconn *conn, vacuumingOptions *vacopts,
- SimpleStringList *objects, bool echo)
-{
- PQExpBufferData buf;
- PQExpBufferData catalog_query;
- PGresult *res;
- SimpleStringListCell *cell;
- SimpleStringList *found_objs = palloc0(sizeof(SimpleStringList));
- bool objects_listed = false;
-
- initPQExpBuffer(&catalog_query);
- for (cell = objects ? objects->head : NULL; cell; cell = cell->next)
- {
- char *just_table = NULL;
- const char *just_columns = NULL;
-
- if (!objects_listed)
- {
- appendPQExpBufferStr(&catalog_query,
- "WITH listed_objects (object_oid, column_list) "
- "AS (\n VALUES (");
- objects_listed = true;
- }
- else
- appendPQExpBufferStr(&catalog_query, ",\n (");
-
- if (objfilter & (OBJFILTER_SCHEMA | OBJFILTER_SCHEMA_EXCLUDE))
- {
- appendStringLiteralConn(&catalog_query, cell->val, conn);
- appendPQExpBufferStr(&catalog_query, "::pg_catalog.regnamespace, ");
- }
-
- if (objfilter & OBJFILTER_TABLE)
- {
- /*
- * Split relation and column names given by the user, this is used
- * to feed the CTE with values on which are performed pre-run
- * validity checks as well. For now these happen only on the
- * relation name.
- */
- splitTableColumnsSpec(cell->val, PQclientEncoding(conn),
- &just_table, &just_columns);
-
- appendStringLiteralConn(&catalog_query, just_table, conn);
- appendPQExpBufferStr(&catalog_query, "::pg_catalog.regclass, ");
- }
-
- if (just_columns && just_columns[0] != '\0')
- appendStringLiteralConn(&catalog_query, just_columns, conn);
- else
- appendPQExpBufferStr(&catalog_query, "NULL");
-
- appendPQExpBufferStr(&catalog_query, "::pg_catalog.text)");
-
- pg_free(just_table);
- }
-
- /* Finish formatting the CTE */
- if (objects_listed)
- appendPQExpBufferStr(&catalog_query, "\n)\n");
-
- appendPQExpBufferStr(&catalog_query, "SELECT c.relname, ns.nspname");
-
- if (objects_listed)
- appendPQExpBufferStr(&catalog_query, ", listed_objects.column_list");
-
- appendPQExpBufferStr(&catalog_query,
- " FROM pg_catalog.pg_class c\n"
- " JOIN pg_catalog.pg_namespace ns"
- " ON c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
- " CROSS JOIN LATERAL (SELECT c.relkind IN ("
- CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
- CppAsString2(RELKIND_PARTITIONED_INDEX) ")) as p (inherited)\n"
- " LEFT JOIN pg_catalog.pg_class t"
- " ON c.reltoastrelid OPERATOR(pg_catalog.=) t.oid\n");
-
- /*
- * Used to match the tables or schemas listed by the user, completing the
- * JOIN clause.
- */
- if (objects_listed)
- {
- appendPQExpBufferStr(&catalog_query, " LEFT JOIN listed_objects"
- " ON listed_objects.object_oid"
- " OPERATOR(pg_catalog.=) ");
-
- if (objfilter & OBJFILTER_TABLE)
- appendPQExpBufferStr(&catalog_query, "c.oid\n");
- else
- appendPQExpBufferStr(&catalog_query, "ns.oid\n");
- }
-
- /*
- * Exclude temporary tables, beginning the WHERE clause.
- */
- appendPQExpBufferStr(&catalog_query,
- " WHERE c.relpersistence OPERATOR(pg_catalog.!=) "
- CppAsString2(RELPERSISTENCE_TEMP) "\n");
-
- /*
- * Used to match the tables or schemas listed by the user, for the WHERE
- * clause.
- */
- if (objects_listed)
- {
- if (objfilter & OBJFILTER_SCHEMA_EXCLUDE)
- appendPQExpBufferStr(&catalog_query,
- " AND listed_objects.object_oid IS NULL\n");
- else
- appendPQExpBufferStr(&catalog_query,
- " AND listed_objects.object_oid IS NOT NULL\n");
- }
-
- /*
- * If no tables were listed, filter for the relevant relation types. If
- * tables were given via --table, don't bother filtering by relation type.
- * Instead, let the server decide whether a given relation can be
- * processed in which case the user will know about it.
- */
- if ((objfilter & OBJFILTER_TABLE) == 0)
- {
- /*
- * vacuumdb should generally follow the behavior of the underlying
- * VACUUM and ANALYZE commands. If analyze_only is true, process
- * regular tables, materialized views, and partitioned tables, just
- * like ANALYZE (with no specific target tables) does. Otherwise,
- * process only regular tables and materialized views, since VACUUM
- * skips partitioned tables when no target tables are specified.
- */
- if (vacopts->analyze_only)
- appendPQExpBufferStr(&catalog_query,
- " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
- CppAsString2(RELKIND_RELATION) ", "
- CppAsString2(RELKIND_MATVIEW) ", "
- CppAsString2(RELKIND_PARTITIONED_TABLE) "])\n");
- else
- appendPQExpBufferStr(&catalog_query,
- " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
- CppAsString2(RELKIND_RELATION) ", "
- CppAsString2(RELKIND_MATVIEW) "])\n");
-
- }
-
- /*
- * For --min-xid-age and --min-mxid-age, the age of the relation is the
- * greatest of the ages of the main relation and its associated TOAST
- * table. The commands generated by vacuumdb will also process the TOAST
- * table for the relation if necessary, so it does not need to be
- * considered separately.
- */
- if (vacopts->min_xid_age != 0)
- {
- appendPQExpBuffer(&catalog_query,
- " AND GREATEST(pg_catalog.age(c.relfrozenxid),"
- " pg_catalog.age(t.relfrozenxid)) "
- " OPERATOR(pg_catalog.>=) '%d'::pg_catalog.int4\n"
- " AND c.relfrozenxid OPERATOR(pg_catalog.!=)"
- " '0'::pg_catalog.xid\n",
- vacopts->min_xid_age);
- }
-
- if (vacopts->min_mxid_age != 0)
- {
- appendPQExpBuffer(&catalog_query,
- " AND GREATEST(pg_catalog.mxid_age(c.relminmxid),"
- " pg_catalog.mxid_age(t.relminmxid)) OPERATOR(pg_catalog.>=)"
- " '%d'::pg_catalog.int4\n"
- " AND c.relminmxid OPERATOR(pg_catalog.!=)"
- " '0'::pg_catalog.xid\n",
- vacopts->min_mxid_age);
- }
-
- if (vacopts->missing_stats_only)
- {
- appendPQExpBufferStr(&catalog_query, " AND (\n");
-
- /* regular stats */
- appendPQExpBufferStr(&catalog_query,
- " EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
- " WHERE a.attrelid OPERATOR(pg_catalog.=) c.oid\n"
- " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
- " AND NOT a.attisdropped\n"
- " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
- " AND a.attgenerated OPERATOR(pg_catalog.<>) "
- CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
- " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
- " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
- " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
- " AND s.stainherit OPERATOR(pg_catalog.=) p.inherited))\n");
-
- /* extended stats */
- appendPQExpBufferStr(&catalog_query,
- " OR EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext e\n"
- " WHERE e.stxrelid OPERATOR(pg_catalog.=) c.oid\n"
- " AND e.stxstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
- " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext_data d\n"
- " WHERE d.stxoid OPERATOR(pg_catalog.=) e.oid\n"
- " AND d.stxdinherit OPERATOR(pg_catalog.=) p.inherited))\n");
-
- /* expression indexes */
- appendPQExpBufferStr(&catalog_query,
- " OR EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
- " JOIN pg_catalog.pg_index i"
- " ON i.indexrelid OPERATOR(pg_catalog.=) a.attrelid\n"
- " WHERE i.indrelid OPERATOR(pg_catalog.=) c.oid\n"
- " AND i.indkey[a.attnum OPERATOR(pg_catalog.-) 1::pg_catalog.int2]"
- " OPERATOR(pg_catalog.=) 0::pg_catalog.int2\n"
- " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
- " AND NOT a.attisdropped\n"
- " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
- " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
- " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
- " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
- " AND s.stainherit OPERATOR(pg_catalog.=) p.inherited))\n");
-
- /* inheritance and regular stats */
- appendPQExpBufferStr(&catalog_query,
- " OR EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
- " WHERE a.attrelid OPERATOR(pg_catalog.=) c.oid\n"
- " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
- " AND NOT a.attisdropped\n"
- " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
- " AND a.attgenerated OPERATOR(pg_catalog.<>) "
- CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
- " AND c.relhassubclass\n"
- " AND NOT p.inherited\n"
- " AND EXISTS (SELECT NULL FROM pg_catalog.pg_inherits h\n"
- " WHERE h.inhparent OPERATOR(pg_catalog.=) c.oid)\n"
- " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
- " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
- " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
- " AND s.stainherit))\n");
-
- /* inheritance and extended stats */
- appendPQExpBufferStr(&catalog_query,
- " OR EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext e\n"
- " WHERE e.stxrelid OPERATOR(pg_catalog.=) c.oid\n"
- " AND e.stxstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
- " AND c.relhassubclass\n"
- " AND NOT p.inherited\n"
- " AND EXISTS (SELECT NULL FROM pg_catalog.pg_inherits h\n"
- " WHERE h.inhparent OPERATOR(pg_catalog.=) c.oid)\n"
- " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext_data d\n"
- " WHERE d.stxoid OPERATOR(pg_catalog.=) e.oid\n"
- " AND d.stxdinherit))\n");
-
- appendPQExpBufferStr(&catalog_query, " )\n");
- }
-
- /*
- * Execute the catalog query. We use the default search_path for this
- * query for consistency with table lookups done elsewhere by the user.
- */
- appendPQExpBufferStr(&catalog_query, " ORDER BY c.relpages DESC;");
- executeCommand(conn, "RESET search_path;", echo);
- res = executeQuery(conn, catalog_query.data, echo);
- termPQExpBuffer(&catalog_query);
- PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
-
- /*
- * Build qualified identifiers for each table, including the column list
- * if given.
- */
- initPQExpBuffer(&buf);
- for (int i = 0; i < PQntuples(res); i++)
- {
- appendPQExpBufferStr(&buf,
- fmtQualifiedIdEnc(PQgetvalue(res, i, 1),
- PQgetvalue(res, i, 0),
- PQclientEncoding(conn)));
-
- if (objects_listed && !PQgetisnull(res, i, 2))
- appendPQExpBufferStr(&buf, PQgetvalue(res, i, 2));
-
- simple_string_list_append(found_objs, buf.data);
- resetPQExpBuffer(&buf);
- }
- termPQExpBuffer(&buf);
- PQclear(res);
-
- return found_objs;
-}
-
-/*
- * Vacuum/analyze all connectable databases.
- *
- * In analyze-in-stages mode, we process all databases in one stage before
- * moving on to the next stage. That ensure minimal stats are available
- * quickly everywhere before generating more detailed ones.
- */
-static void
-vacuum_all_databases(ConnParams *cparams,
- vacuumingOptions *vacopts,
- bool analyze_in_stages,
- SimpleStringList *objects,
- int concurrentCons,
- const char *progname, bool echo, bool quiet)
-{
- PGconn *conn;
- PGresult *result;
- int stage;
- int i;
-
- conn = connectMaintenanceDatabase(cparams, progname, echo);
- result = executeQuery(conn,
- "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;",
- echo);
- PQfinish(conn);
-
- if (analyze_in_stages)
- {
- SimpleStringList **found_objs = NULL;
-
- if (vacopts->missing_stats_only)
- found_objs = palloc0(PQntuples(result) * sizeof(SimpleStringList *));
-
- /*
- * When analyzing all databases in stages, we analyze them all in the
- * fastest stage first, so that initial statistics become available
- * for all of them as soon as possible.
- *
- * This means we establish several times as many connections, but
- * that's a secondary consideration.
- */
- for (stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
- {
- for (i = 0; i < PQntuples(result); i++)
- {
- cparams->override_dbname = PQgetvalue(result, i, 0);
-
- vacuum_one_database(cparams, vacopts,
- stage,
- objects,
- vacopts->missing_stats_only ? &found_objs[i] : NULL,
- concurrentCons,
- progname, echo, quiet);
- }
- }
- }
- else
- {
- for (i = 0; i < PQntuples(result); i++)
- {
- cparams->override_dbname = PQgetvalue(result, i, 0);
-
- vacuum_one_database(cparams, vacopts,
- ANALYZE_NO_STAGE,
- objects, NULL,
- concurrentCons,
- progname, echo, quiet);
- }
- }
-
- PQclear(result);
-}
-
-/*
- * Construct a vacuum/analyze command to run based on the given options, in the
- * given string buffer, which may contain previous garbage.
- *
- * The table name used must be already properly quoted. The command generated
- * depends on the server version involved and it is semicolon-terminated.
- */
-static void
-prepare_vacuum_command(PQExpBuffer sql, int serverVersion,
- vacuumingOptions *vacopts, const char *table)
-{
- const char *paren = " (";
- const char *comma = ", ";
- const char *sep = paren;
-
- resetPQExpBuffer(sql);
-
- if (vacopts->analyze_only)
- {
- appendPQExpBufferStr(sql, "ANALYZE");
-
- /* parenthesized grammar of ANALYZE is supported since v11 */
- if (serverVersion >= 110000)
- {
- if (vacopts->skip_locked)
- {
- /* SKIP_LOCKED is supported since v12 */
- Assert(serverVersion >= 120000);
- appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
- sep = comma;
- }
- if (vacopts->verbose)
- {
- appendPQExpBuffer(sql, "%sVERBOSE", sep);
- sep = comma;
- }
- if (vacopts->buffer_usage_limit)
- {
- Assert(serverVersion >= 160000);
- appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
- vacopts->buffer_usage_limit);
- sep = comma;
- }
- if (sep != paren)
- appendPQExpBufferChar(sql, ')');
- }
- else
- {
- if (vacopts->verbose)
- appendPQExpBufferStr(sql, " VERBOSE");
- }
- }
- else
- {
- appendPQExpBufferStr(sql, "VACUUM");
-
- /* parenthesized grammar of VACUUM is supported since v9.0 */
- if (serverVersion >= 90000)
- {
- if (vacopts->disable_page_skipping)
- {
- /* DISABLE_PAGE_SKIPPING is supported since v9.6 */
- Assert(serverVersion >= 90600);
- appendPQExpBuffer(sql, "%sDISABLE_PAGE_SKIPPING", sep);
- sep = comma;
- }
- if (vacopts->no_index_cleanup)
- {
- /* "INDEX_CLEANUP FALSE" has been supported since v12 */
- Assert(serverVersion >= 120000);
- Assert(!vacopts->force_index_cleanup);
- appendPQExpBuffer(sql, "%sINDEX_CLEANUP FALSE", sep);
- sep = comma;
- }
- if (vacopts->force_index_cleanup)
- {
- /* "INDEX_CLEANUP TRUE" has been supported since v12 */
- Assert(serverVersion >= 120000);
- Assert(!vacopts->no_index_cleanup);
- appendPQExpBuffer(sql, "%sINDEX_CLEANUP TRUE", sep);
- sep = comma;
- }
- if (!vacopts->do_truncate)
- {
- /* TRUNCATE is supported since v12 */
- Assert(serverVersion >= 120000);
- appendPQExpBuffer(sql, "%sTRUNCATE FALSE", sep);
- sep = comma;
- }
- if (!vacopts->process_main)
- {
- /* PROCESS_MAIN is supported since v16 */
- Assert(serverVersion >= 160000);
- appendPQExpBuffer(sql, "%sPROCESS_MAIN FALSE", sep);
- sep = comma;
- }
- if (!vacopts->process_toast)
- {
- /* PROCESS_TOAST is supported since v14 */
- Assert(serverVersion >= 140000);
- appendPQExpBuffer(sql, "%sPROCESS_TOAST FALSE", sep);
- sep = comma;
- }
- if (vacopts->skip_database_stats)
- {
- /* SKIP_DATABASE_STATS is supported since v16 */
- Assert(serverVersion >= 160000);
- appendPQExpBuffer(sql, "%sSKIP_DATABASE_STATS", sep);
- sep = comma;
- }
- if (vacopts->skip_locked)
- {
- /* SKIP_LOCKED is supported since v12 */
- Assert(serverVersion >= 120000);
- appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
- sep = comma;
- }
- if (vacopts->full)
- {
- appendPQExpBuffer(sql, "%sFULL", sep);
- sep = comma;
- }
- if (vacopts->freeze)
- {
- appendPQExpBuffer(sql, "%sFREEZE", sep);
- sep = comma;
- }
- if (vacopts->verbose)
- {
- appendPQExpBuffer(sql, "%sVERBOSE", sep);
- sep = comma;
- }
- if (vacopts->and_analyze)
- {
- appendPQExpBuffer(sql, "%sANALYZE", sep);
- sep = comma;
- }
- if (vacopts->parallel_workers >= 0)
- {
- /* PARALLEL is supported since v13 */
- Assert(serverVersion >= 130000);
- appendPQExpBuffer(sql, "%sPARALLEL %d", sep,
- vacopts->parallel_workers);
- sep = comma;
- }
- if (vacopts->buffer_usage_limit)
- {
- Assert(serverVersion >= 160000);
- appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
- vacopts->buffer_usage_limit);
- sep = comma;
- }
- if (sep != paren)
- appendPQExpBufferChar(sql, ')');
- }
- else
- {
- if (vacopts->full)
- appendPQExpBufferStr(sql, " FULL");
- if (vacopts->freeze)
- appendPQExpBufferStr(sql, " FREEZE");
- if (vacopts->verbose)
- appendPQExpBufferStr(sql, " VERBOSE");
- if (vacopts->and_analyze)
- appendPQExpBufferStr(sql, " ANALYZE");
- }
- }
-
- appendPQExpBuffer(sql, " %s;", table);
-}
-
-/*
- * Send a vacuum/analyze command to the server, returning after sending the
- * command.
- *
- * Any errors during command execution are reported to stderr.
- */
-static void
-run_vacuum_command(PGconn *conn, const char *sql, bool echo,
- const char *table)
-{
- bool status;
-
- if (echo)
- printf("%s\n", sql);
-
- status = PQsendQuery(conn, sql) == 1;
-
- if (!status)
- {
- if (table)
- pg_log_error("vacuuming of table \"%s\" in database \"%s\" failed: %s",
- table, PQdb(conn), PQerrorMessage(conn));
- else
- pg_log_error("vacuuming of database \"%s\" failed: %s",
- PQdb(conn), PQerrorMessage(conn));
- }
-}
static void
help(const char *progname)
diff --git a/src/bin/scripts/vacuuming.c b/src/bin/scripts/vacuuming.c
new file mode 100644
index 00000000000..b9f2e507557
--- /dev/null
+++ b/src/bin/scripts/vacuuming.c
@@ -0,0 +1,1012 @@
+/*-------------------------------------------------------------------------
+ * vacuuming.c
+ * Helper routines for vacuumdb
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/scripts/vacuuming.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include "catalog/pg_attribute_d.h"
+#include "catalog/pg_class_d.h"
+#include "common/connect.h"
+#include "common/logging.h"
+#include "fe_utils/cancel.h"
+#include "fe_utils/option_utils.h"
+#include "fe_utils/parallel_slot.h"
+#include "fe_utils/query_utils.h"
+#include "fe_utils/string_utils.h"
+#include "vacuuming.h"
+
+
+static int vacuum_one_database(ConnParams *cparams,
+ vacuumingOptions *vacopts,
+ int stage,
+ VacObjFilter objfilter,
+ SimpleStringList *objects,
+ SimpleStringList **found_objs,
+ int concurrentCons,
+ const char *progname, bool echo, bool quiet);
+static int vacuum_all_databases(ConnParams *cparams,
+ vacuumingOptions *vacopts,
+ bool analyze_in_stages,
+ VacObjFilter objfilter,
+ SimpleStringList *objects,
+ int concurrentCons,
+ const char *progname, bool echo, bool quiet);
+static SimpleStringList *retrieve_objects(PGconn *conn,
+ vacuumingOptions *vacopts,
+ VacObjFilter objfilter,
+ SimpleStringList *objects,
+ bool echo);
+static void prepare_vacuum_command(PGconn *conn, PQExpBuffer sql,
+ vacuumingOptions *vacopts, const char *table);
+static void run_vacuum_command(PGconn *conn, const char *sql, bool echo,
+ const char *table);
+
+/*
+ * Executes vacuum/analyze as indicated, or dies in case of failure.
+ */
+int
+vacuuming_main(ConnParams *cparams, const char *dbname,
+ const char *maintenance_db, vacuumingOptions *vacopts,
+ VacObjFilter objfilter, SimpleStringList *objects,
+ int tbl_count, bool analyze_in_stages, int concurrentCons,
+ const char *progname, bool echo, bool quiet)
+{
+ setup_cancel_handler(NULL);
+
+ /* Avoid opening extra connections. */
+ if (tbl_count && (concurrentCons > tbl_count))
+ concurrentCons = tbl_count;
+
+ if (objfilter & OBJFILTER_ALL_DBS)
+ {
+ cparams->dbname = maintenance_db;
+
+ return vacuum_all_databases(cparams, vacopts,
+ analyze_in_stages,
+ objfilter, objects,
+ concurrentCons,
+ progname, echo, quiet);
+ }
+ else
+ {
+ if (dbname == NULL)
+ {
+ if (getenv("PGDATABASE"))
+ dbname = getenv("PGDATABASE");
+ else if (getenv("PGUSER"))
+ dbname = getenv("PGUSER");
+ else
+ dbname = get_user_name_or_exit(progname);
+ }
+
+ cparams->dbname = dbname;
+
+ if (analyze_in_stages)
+ {
+ SimpleStringList *found_objs = NULL;
+
+ for (int stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
+ {
+ int ret;
+
+ ret = vacuum_one_database(cparams, vacopts,
+ stage,
+ objfilter, objects,
+ vacopts->missing_stats_only ? &found_objs : NULL,
+ concurrentCons,
+ progname, echo, quiet);
+ if (ret != 0)
+ return ret;
+ }
+
+ return EXIT_SUCCESS;
+ }
+ else
+ return vacuum_one_database(cparams, vacopts,
+ ANALYZE_NO_STAGE,
+ objfilter, objects, NULL,
+ concurrentCons,
+ progname, echo, quiet);
+ }
+}
+
+
+/*
+ * vacuum_one_database
+ *
+ * Process tables in the given database.
+ *
+ * There are two ways to specify the list of objects to process:
+ *
+ * 1) The "found_objs" parameter is a double pointer to a fully qualified list
+ * of objects to process, as returned by a previous call to
+ * vacuum_one_database().
+ *
+ * a) If both "found_objs" (the double pointer) and "*found_objs" (the
+ * once-dereferenced double pointer) are not NULL, this list takes
+ * priority, and anything specified in "objects" is ignored.
+ *
+ * b) If "found_objs" (the double pointer) is not NULL but "*found_objs"
+ * (the once-dereferenced double pointer) _is_ NULL, the "objects"
+ * parameter takes priority, and the results of the catalog query
+ * described in (2) are stored in "found_objs".
+ *
+ * c) If "found_objs" (the double pointer) is NULL, the "objects"
+ * parameter again takes priority, and the results of the catalog query
+ * are not saved.
+ *
+ * 2) The "objects" parameter is a user-specified list of objects to process.
+ * When (1b) or (1c) applies, this function performs a catalog query to
+ * retrieve a fully qualified list of objects to process, as described
+ * below.
+ *
+ * a) If "objects" is not NULL, the catalog query gathers only the objects
+ * listed in "objects".
+ *
+ * b) If "objects" is NULL, all tables in the database are gathered.
+ *
+ * Note that this function is only concerned with running exactly one stage
+ * when in analyze-in-stages mode; caller must iterate on us if necessary.
+ *
+ * If concurrentCons is > 1, multiple connections are used to vacuum tables
+ * in parallel.
+ */
+static int
+vacuum_one_database(ConnParams *cparams,
+ vacuumingOptions *vacopts,
+ int stage,
+ VacObjFilter objfilter, SimpleStringList *objects,
+ SimpleStringList **found_objs,
+ int concurrentCons,
+ const char *progname, bool echo, bool quiet)
+{
+ PQExpBufferData sql;
+ PGconn *conn;
+ SimpleStringListCell *cell;
+ ParallelSlotArray *sa;
+ int ntups = 0;
+ const char *initcmd;
+ SimpleStringList *retobjs = NULL;
+ int ret = EXIT_SUCCESS;
+ const char *stage_commands[] = {
+ "SET default_statistics_target=1; SET vacuum_cost_delay=0;",
+ "SET default_statistics_target=10; RESET vacuum_cost_delay;",
+ "RESET default_statistics_target;"
+ };
+ const char *stage_messages[] = {
+ gettext_noop("Generating minimal optimizer statistics (1 target)"),
+ gettext_noop("Generating medium optimizer statistics (10 targets)"),
+ gettext_noop("Generating default (full) optimizer statistics")
+ };
+
+ Assert(stage == ANALYZE_NO_STAGE ||
+ (stage >= 0 && stage < ANALYZE_NUM_STAGES));
+
+ conn = connectDatabase(cparams, progname, echo, false, true);
+
+ if (vacopts->disable_page_skipping && PQserverVersion(conn) < 90600)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "disable-page-skipping", "9.6");
+ }
+
+ if (vacopts->no_index_cleanup && PQserverVersion(conn) < 120000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "no-index-cleanup", "12");
+ }
+
+ if (vacopts->force_index_cleanup && PQserverVersion(conn) < 120000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "force-index-cleanup", "12");
+ }
+
+ if (!vacopts->do_truncate && PQserverVersion(conn) < 120000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "no-truncate", "12");
+ }
+
+ if (!vacopts->process_main && PQserverVersion(conn) < 160000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "no-process-main", "16");
+ }
+
+ if (!vacopts->process_toast && PQserverVersion(conn) < 140000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "no-process-toast", "14");
+ }
+
+ if (vacopts->skip_locked && PQserverVersion(conn) < 120000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "skip-locked", "12");
+ }
+
+ if (vacopts->min_xid_age != 0 && PQserverVersion(conn) < 90600)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "--min-xid-age", "9.6");
+ }
+
+ if (vacopts->min_mxid_age != 0 && PQserverVersion(conn) < 90600)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "--min-mxid-age", "9.6");
+ }
+
+ if (vacopts->parallel_workers >= 0 && PQserverVersion(conn) < 130000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "--parallel", "13");
+ }
+
+ if (vacopts->buffer_usage_limit && PQserverVersion(conn) < 160000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "--buffer-usage-limit", "16");
+ }
+
+ if (vacopts->missing_stats_only && PQserverVersion(conn) < 150000)
+ {
+ PQfinish(conn);
+ pg_fatal("cannot use the \"%s\" option on server versions older than PostgreSQL %s",
+ "--missing-stats-only", "15");
+ }
+
+ /* skip_database_stats is used automatically if server supports it */
+ vacopts->skip_database_stats = (PQserverVersion(conn) >= 160000);
+
+ if (!quiet)
+ {
+ if (stage != ANALYZE_NO_STAGE)
+ printf(_("%s: processing database \"%s\": %s\n"),
+ progname, PQdb(conn), _(stage_messages[stage]));
+ else
+ printf(_("%s: vacuuming database \"%s\"\n"),
+ progname, PQdb(conn));
+ fflush(stdout);
+ }
+
+ /*
+ * If the caller provided the results of a previous catalog query, just
+ * use that. Otherwise, run the catalog query ourselves and set the
+ * return variable if provided.
+ */
+ if (found_objs && *found_objs)
+ retobjs = *found_objs;
+ else
+ {
+ retobjs = retrieve_objects(conn, vacopts, objfilter, objects, echo);
+ if (found_objs)
+ *found_objs = retobjs;
+ }
+
+ /*
+ * Count the number of objects in the catalog query result. If there are
+ * none, we are done.
+ */
+ for (cell = retobjs ? retobjs->head : NULL; cell; cell = cell->next)
+ ntups++;
+
+ if (ntups == 0)
+ {
+ PQfinish(conn);
+ return EXIT_SUCCESS;
+ }
+
+ /*
+ * Ensure concurrentCons is sane. If there are more connections than
+ * vacuumable relations, we don't need to use them all.
+ */
+ if (concurrentCons > ntups)
+ concurrentCons = ntups;
+ if (concurrentCons <= 0)
+ concurrentCons = 1;
+
+ /*
+ * All slots need to be prepared to run the appropriate analyze stage, if
+ * caller requested that mode. We have to prepare the initial connection
+ * ourselves before setting up the slots.
+ */
+ if (stage == ANALYZE_NO_STAGE)
+ initcmd = NULL;
+ else
+ {
+ initcmd = stage_commands[stage];
+ executeCommand(conn, initcmd, echo);
+ }
+
+ /*
+ * Setup the database connections. We reuse the connection we already have
+ * for the first slot. If not in parallel mode, the first slot in the
+ * array contains the connection.
+ */
+ sa = ParallelSlotsSetup(concurrentCons, cparams, progname, echo, initcmd);
+ ParallelSlotsAdoptConn(sa, conn);
+
+ initPQExpBuffer(&sql);
+
+ cell = retobjs->head;
+ do
+ {
+ const char *tabname = cell->val;
+ ParallelSlot *free_slot;
+
+ if (CancelRequested)
+ {
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+
+ free_slot = ParallelSlotsGetIdle(sa, NULL);
+ if (!free_slot)
+ {
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+
+ prepare_vacuum_command(free_slot->connection, &sql,
+ vacopts, tabname);
+
+ /*
+ * Execute the vacuum. All errors are handled in processQueryResult
+ * through ParallelSlotsGetIdle.
+ */
+ ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
+ run_vacuum_command(free_slot->connection, sql.data,
+ echo, tabname);
+
+ cell = cell->next;
+ } while (cell != NULL);
+
+ if (!ParallelSlotsWaitCompletion(sa))
+ {
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+
+ /* If we used SKIP_DATABASE_STATS, mop up with ONLY_DATABASE_STATS */
+ if (vacopts->skip_database_stats && stage == ANALYZE_NO_STAGE &&
+ !vacopts->analyze_only)
+ {
+ const char *cmd = "VACUUM (ONLY_DATABASE_STATS);";
+ ParallelSlot *free_slot = ParallelSlotsGetIdle(sa, NULL);
+
+ if (!free_slot)
+ {
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+
+ ParallelSlotSetHandler(free_slot, TableCommandResultHandler, NULL);
+ run_vacuum_command(free_slot->connection, cmd, echo, NULL);
+
+ if (!ParallelSlotsWaitCompletion(sa))
+ ret = EXIT_FAILURE;
+ }
+
+finish:
+ ParallelSlotsTerminate(sa);
+ pg_free(sa);
+
+ termPQExpBuffer(&sql);
+
+ return ret;
+}
+
+/*
+ * Vacuum/analyze all connectable databases.
+ *
+ * In analyze-in-stages mode, we process all databases in one stage before
+ * moving on to the next stage. That ensure minimal stats are available
+ * quickly everywhere before generating more detailed ones.
+ */
+static int
+vacuum_all_databases(ConnParams *cparams,
+ vacuumingOptions *vacopts,
+ bool analyze_in_stages,
+ VacObjFilter objfilter,
+ SimpleStringList *objects,
+ int concurrentCons,
+ const char *progname, bool echo, bool quiet)
+{
+ PGconn *conn;
+ PGresult *result;
+
+ conn = connectMaintenanceDatabase(cparams, progname, echo);
+ result = executeQuery(conn,
+ "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;",
+ echo);
+ PQfinish(conn);
+
+ if (analyze_in_stages)
+ {
+ SimpleStringList **found_objs = NULL;
+
+ if (vacopts->missing_stats_only)
+ found_objs = palloc0(PQntuples(result) * sizeof(SimpleStringList *));
+
+ /*
+ * When analyzing all databases in stages, we analyze them all in the
+ * fastest stage first, so that initial statistics become available
+ * for all of them as soon as possible.
+ *
+ * This means we establish several times as many connections, but
+ * that's a secondary consideration.
+ */
+ for (int stage = 0; stage < ANALYZE_NUM_STAGES; stage++)
+ {
+ for (int i = 0; i < PQntuples(result); i++)
+ {
+ int ret;
+
+ cparams->override_dbname = PQgetvalue(result, i, 0);
+ ret = vacuum_one_database(cparams, vacopts,
+ stage,
+ objfilter, objects,
+ vacopts->missing_stats_only ? &found_objs[i] : NULL,
+ concurrentCons,
+ progname, echo, quiet);
+ if (ret != EXIT_SUCCESS)
+ return ret;
+ }
+ }
+ }
+ else
+ {
+ for (int i = 0; i < PQntuples(result); i++)
+ {
+ int ret;
+
+ cparams->override_dbname = PQgetvalue(result, i, 0);
+ ret = vacuum_one_database(cparams, vacopts,
+ ANALYZE_NO_STAGE,
+ objfilter, objects,
+ NULL,
+ concurrentCons,
+ progname, echo, quiet);
+ if (ret != EXIT_SUCCESS)
+ return ret;
+ }
+ }
+
+ PQclear(result);
+
+ return EXIT_SUCCESS;
+}
+
+/*
+ * Prepare the list of tables to process by querying the catalogs.
+ *
+ * Since we execute the constructed query with the default search_path (which
+ * could be unsafe), everything in this query MUST be fully qualified.
+ *
+ * First, build a WITH clause for the catalog query if any tables were
+ * specified, with a set of values made of relation names and their optional
+ * set of columns. This is used to match any provided column lists with the
+ * generated qualified identifiers and to filter for the tables provided via
+ * --table. If a listed table does not exist, the catalog query will fail.
+ */
+static SimpleStringList *
+retrieve_objects(PGconn *conn, vacuumingOptions *vacopts,
+ VacObjFilter objfilter, SimpleStringList *objects, bool echo)
+{
+ PQExpBufferData buf;
+ PQExpBufferData catalog_query;
+ PGresult *res;
+ SimpleStringListCell *cell;
+ SimpleStringList *found_objs = palloc0(sizeof(SimpleStringList));
+ bool objects_listed = false;
+
+ initPQExpBuffer(&catalog_query);
+ for (cell = objects ? objects->head : NULL; cell; cell = cell->next)
+ {
+ char *just_table = NULL;
+ const char *just_columns = NULL;
+
+ if (!objects_listed)
+ {
+ appendPQExpBufferStr(&catalog_query,
+ "WITH listed_objects (object_oid, column_list) AS (\n"
+ " VALUES (");
+ objects_listed = true;
+ }
+ else
+ appendPQExpBufferStr(&catalog_query, ",\n (");
+
+ if (objfilter & (OBJFILTER_SCHEMA | OBJFILTER_SCHEMA_EXCLUDE))
+ {
+ appendStringLiteralConn(&catalog_query, cell->val, conn);
+ appendPQExpBufferStr(&catalog_query, "::pg_catalog.regnamespace, ");
+ }
+
+ if (objfilter & OBJFILTER_TABLE)
+ {
+ /*
+ * Split relation and column names given by the user, this is used
+ * to feed the CTE with values on which are performed pre-run
+ * validity checks as well. For now these happen only on the
+ * relation name.
+ */
+ splitTableColumnsSpec(cell->val, PQclientEncoding(conn),
+ &just_table, &just_columns);
+
+ appendStringLiteralConn(&catalog_query, just_table, conn);
+ appendPQExpBufferStr(&catalog_query, "::pg_catalog.regclass, ");
+ }
+
+ if (just_columns && just_columns[0] != '\0')
+ appendStringLiteralConn(&catalog_query, just_columns, conn);
+ else
+ appendPQExpBufferStr(&catalog_query, "NULL");
+
+ appendPQExpBufferStr(&catalog_query, "::pg_catalog.text)");
+
+ pg_free(just_table);
+ }
+
+ /* Finish formatting the CTE */
+ if (objects_listed)
+ appendPQExpBufferStr(&catalog_query, "\n)\n");
+
+ appendPQExpBufferStr(&catalog_query, "SELECT c.relname, ns.nspname");
+
+ if (objects_listed)
+ appendPQExpBufferStr(&catalog_query, ", listed_objects.column_list");
+
+ appendPQExpBufferStr(&catalog_query,
+ " FROM pg_catalog.pg_class c\n"
+ " JOIN pg_catalog.pg_namespace ns"
+ " ON c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
+ " CROSS JOIN LATERAL (SELECT c.relkind IN ("
+ CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
+ CppAsString2(RELKIND_PARTITIONED_INDEX) ")) as p (inherited)\n"
+ " LEFT JOIN pg_catalog.pg_class t"
+ " ON c.reltoastrelid OPERATOR(pg_catalog.=) t.oid\n");
+
+ /*
+ * Used to match the tables or schemas listed by the user, completing the
+ * JOIN clause.
+ */
+ if (objects_listed)
+ {
+ appendPQExpBufferStr(&catalog_query, " LEFT JOIN listed_objects"
+ " ON listed_objects.object_oid"
+ " OPERATOR(pg_catalog.=) ");
+
+ if (objfilter & OBJFILTER_TABLE)
+ appendPQExpBufferStr(&catalog_query, "c.oid\n");
+ else
+ appendPQExpBufferStr(&catalog_query, "ns.oid\n");
+ }
+
+ /*
+ * Exclude temporary tables, beginning the WHERE clause.
+ */
+ appendPQExpBufferStr(&catalog_query,
+ " WHERE c.relpersistence OPERATOR(pg_catalog.!=) "
+ CppAsString2(RELPERSISTENCE_TEMP) "\n");
+
+ /*
+ * Used to match the tables or schemas listed by the user, for the WHERE
+ * clause.
+ */
+ if (objects_listed)
+ {
+ if (objfilter & OBJFILTER_SCHEMA_EXCLUDE)
+ appendPQExpBufferStr(&catalog_query,
+ " AND listed_objects.object_oid IS NULL\n");
+ else
+ appendPQExpBufferStr(&catalog_query,
+ " AND listed_objects.object_oid IS NOT NULL\n");
+ }
+
+ /*
+ * If no tables were listed, filter for the relevant relation types. If
+ * tables were given via --table, don't bother filtering by relation type.
+ * Instead, let the server decide whether a given relation can be
+ * processed in which case the user will know about it.
+ */
+ if ((objfilter & OBJFILTER_TABLE) == 0)
+ {
+ /*
+ * vacuumdb should generally follow the behavior of the underlying
+ * VACUUM and ANALYZE commands. If analyze_only is true, process
+ * regular tables, materialized views, and partitioned tables, just
+ * like ANALYZE (with no specific target tables) does. Otherwise,
+ * process only regular tables and materialized views, since VACUUM
+ * skips partitioned tables when no target tables are specified.
+ */
+ if (vacopts->analyze_only)
+ appendPQExpBufferStr(&catalog_query,
+ " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
+ CppAsString2(RELKIND_RELATION) ", "
+ CppAsString2(RELKIND_MATVIEW) ", "
+ CppAsString2(RELKIND_PARTITIONED_TABLE) "])\n");
+ else
+ appendPQExpBufferStr(&catalog_query,
+ " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
+ CppAsString2(RELKIND_RELATION) ", "
+ CppAsString2(RELKIND_MATVIEW) "])\n");
+ }
+
+ /*
+ * For --min-xid-age and --min-mxid-age, the age of the relation is the
+ * greatest of the ages of the main relation and its associated TOAST
+ * table. The commands generated by vacuumdb will also process the TOAST
+ * table for the relation if necessary, so it does not need to be
+ * considered separately.
+ */
+ if (vacopts->min_xid_age != 0)
+ {
+ appendPQExpBuffer(&catalog_query,
+ " AND GREATEST(pg_catalog.age(c.relfrozenxid),"
+ " pg_catalog.age(t.relfrozenxid)) "
+ " OPERATOR(pg_catalog.>=) '%d'::pg_catalog.int4\n"
+ " AND c.relfrozenxid OPERATOR(pg_catalog.!=)"
+ " '0'::pg_catalog.xid\n",
+ vacopts->min_xid_age);
+ }
+
+ if (vacopts->min_mxid_age != 0)
+ {
+ appendPQExpBuffer(&catalog_query,
+ " AND GREATEST(pg_catalog.mxid_age(c.relminmxid),"
+ " pg_catalog.mxid_age(t.relminmxid)) OPERATOR(pg_catalog.>=)"
+ " '%d'::pg_catalog.int4\n"
+ " AND c.relminmxid OPERATOR(pg_catalog.!=)"
+ " '0'::pg_catalog.xid\n",
+ vacopts->min_mxid_age);
+ }
+
+ if (vacopts->missing_stats_only)
+ {
+ appendPQExpBufferStr(&catalog_query, " AND (\n");
+
+ /* regular stats */
+ appendPQExpBufferStr(&catalog_query,
+ " EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
+ " WHERE a.attrelid OPERATOR(pg_catalog.=) c.oid\n"
+ " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
+ " AND NOT a.attisdropped\n"
+ " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+ " AND a.attgenerated OPERATOR(pg_catalog.<>) "
+ CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
+ " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
+ " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
+ " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
+ " AND s.stainherit OPERATOR(pg_catalog.=) p.inherited))\n");
+
+ /* extended stats */
+ appendPQExpBufferStr(&catalog_query,
+ " OR EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext e\n"
+ " WHERE e.stxrelid OPERATOR(pg_catalog.=) c.oid\n"
+ " AND e.stxstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+ " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext_data d\n"
+ " WHERE d.stxoid OPERATOR(pg_catalog.=) e.oid\n"
+ " AND d.stxdinherit OPERATOR(pg_catalog.=) p.inherited))\n");
+
+ /* expression indexes */
+ appendPQExpBufferStr(&catalog_query,
+ " OR EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
+ " JOIN pg_catalog.pg_index i"
+ " ON i.indexrelid OPERATOR(pg_catalog.=) a.attrelid\n"
+ " WHERE i.indrelid OPERATOR(pg_catalog.=) c.oid\n"
+ " AND i.indkey[a.attnum OPERATOR(pg_catalog.-) 1::pg_catalog.int2]"
+ " OPERATOR(pg_catalog.=) 0::pg_catalog.int2\n"
+ " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
+ " AND NOT a.attisdropped\n"
+ " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+ " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
+ " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
+ " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
+ " AND s.stainherit OPERATOR(pg_catalog.=) p.inherited))\n");
+
+ /* inheritance and regular stats */
+ appendPQExpBufferStr(&catalog_query,
+ " OR EXISTS (SELECT NULL FROM pg_catalog.pg_attribute a\n"
+ " WHERE a.attrelid OPERATOR(pg_catalog.=) c.oid\n"
+ " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
+ " AND NOT a.attisdropped\n"
+ " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+ " AND a.attgenerated OPERATOR(pg_catalog.<>) "
+ CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
+ " AND c.relhassubclass\n"
+ " AND NOT p.inherited\n"
+ " AND EXISTS (SELECT NULL FROM pg_catalog.pg_inherits h\n"
+ " WHERE h.inhparent OPERATOR(pg_catalog.=) c.oid)\n"
+ " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
+ " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
+ " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
+ " AND s.stainherit))\n");
+
+ /* inheritance and extended stats */
+ appendPQExpBufferStr(&catalog_query,
+ " OR EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext e\n"
+ " WHERE e.stxrelid OPERATOR(pg_catalog.=) c.oid\n"
+ " AND e.stxstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+ " AND c.relhassubclass\n"
+ " AND NOT p.inherited\n"
+ " AND EXISTS (SELECT NULL FROM pg_catalog.pg_inherits h\n"
+ " WHERE h.inhparent OPERATOR(pg_catalog.=) c.oid)\n"
+ " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic_ext_data d\n"
+ " WHERE d.stxoid OPERATOR(pg_catalog.=) e.oid\n"
+ " AND d.stxdinherit))\n");
+
+ appendPQExpBufferStr(&catalog_query, " )\n");
+ }
+
+ /*
+ * Execute the catalog query. We use the default search_path for this
+ * query for consistency with table lookups done elsewhere by the user.
+ */
+ appendPQExpBufferStr(&catalog_query, " ORDER BY c.relpages DESC;");
+ executeCommand(conn, "RESET search_path;", echo);
+ res = executeQuery(conn, catalog_query.data, echo);
+ termPQExpBuffer(&catalog_query);
+ PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
+
+ /*
+ * Build qualified identifiers for each table, including the column list
+ * if given.
+ */
+ initPQExpBuffer(&buf);
+ for (int i = 0; i < PQntuples(res); i++)
+ {
+ appendPQExpBufferStr(&buf,
+ fmtQualifiedIdEnc(PQgetvalue(res, i, 1),
+ PQgetvalue(res, i, 0),
+ PQclientEncoding(conn)));
+
+ if (objects_listed && !PQgetisnull(res, i, 2))
+ appendPQExpBufferStr(&buf, PQgetvalue(res, i, 2));
+
+ simple_string_list_append(found_objs, buf.data);
+ resetPQExpBuffer(&buf);
+ }
+ termPQExpBuffer(&buf);
+ PQclear(res);
+
+ return found_objs;
+}
+
+/*
+ * Construct a vacuum/analyze command to run based on the given
+ * options, in the given string buffer, which may contain previous garbage.
+ *
+ * The table name used must be already properly quoted. The command generated
+ * depends on the server version involved and it is semicolon-terminated.
+ */
+static void
+prepare_vacuum_command(PGconn *conn, PQExpBuffer sql,
+ vacuumingOptions *vacopts, const char *table)
+{
+ int serverVersion = PQserverVersion(conn);
+ const char *paren = " (";
+ const char *comma = ", ";
+ const char *sep = paren;
+
+ resetPQExpBuffer(sql);
+
+ if (vacopts->analyze_only)
+ {
+ appendPQExpBufferStr(sql, "ANALYZE");
+
+ /* parenthesized grammar of ANALYZE is supported since v11 */
+ if (serverVersion >= 110000)
+ {
+ if (vacopts->skip_locked)
+ {
+ /* SKIP_LOCKED is supported since v12 */
+ Assert(serverVersion >= 120000);
+ appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
+ sep = comma;
+ }
+ if (vacopts->verbose)
+ {
+ appendPQExpBuffer(sql, "%sVERBOSE", sep);
+ sep = comma;
+ }
+ if (vacopts->buffer_usage_limit)
+ {
+ Assert(serverVersion >= 160000);
+ appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
+ vacopts->buffer_usage_limit);
+ sep = comma;
+ }
+ if (sep != paren)
+ appendPQExpBufferChar(sql, ')');
+ }
+ else
+ {
+ if (vacopts->verbose)
+ appendPQExpBufferStr(sql, " VERBOSE");
+ }
+ }
+ else
+ {
+ appendPQExpBufferStr(sql, "VACUUM");
+
+ /* parenthesized grammar of VACUUM is supported since v9.0 */
+ if (serverVersion >= 90000)
+ {
+ if (vacopts->disable_page_skipping)
+ {
+ /* DISABLE_PAGE_SKIPPING is supported since v9.6 */
+ Assert(serverVersion >= 90600);
+ appendPQExpBuffer(sql, "%sDISABLE_PAGE_SKIPPING", sep);
+ sep = comma;
+ }
+ if (vacopts->no_index_cleanup)
+ {
+ /* "INDEX_CLEANUP FALSE" has been supported since v12 */
+ Assert(serverVersion >= 120000);
+ Assert(!vacopts->force_index_cleanup);
+ appendPQExpBuffer(sql, "%sINDEX_CLEANUP FALSE", sep);
+ sep = comma;
+ }
+ if (vacopts->force_index_cleanup)
+ {
+ /* "INDEX_CLEANUP TRUE" has been supported since v12 */
+ Assert(serverVersion >= 120000);
+ Assert(!vacopts->no_index_cleanup);
+ appendPQExpBuffer(sql, "%sINDEX_CLEANUP TRUE", sep);
+ sep = comma;
+ }
+ if (!vacopts->do_truncate)
+ {
+ /* TRUNCATE is supported since v12 */
+ Assert(serverVersion >= 120000);
+ appendPQExpBuffer(sql, "%sTRUNCATE FALSE", sep);
+ sep = comma;
+ }
+ if (!vacopts->process_main)
+ {
+ /* PROCESS_MAIN is supported since v16 */
+ Assert(serverVersion >= 160000);
+ appendPQExpBuffer(sql, "%sPROCESS_MAIN FALSE", sep);
+ sep = comma;
+ }
+ if (!vacopts->process_toast)
+ {
+ /* PROCESS_TOAST is supported since v14 */
+ Assert(serverVersion >= 140000);
+ appendPQExpBuffer(sql, "%sPROCESS_TOAST FALSE", sep);
+ sep = comma;
+ }
+ if (vacopts->skip_database_stats)
+ {
+ /* SKIP_DATABASE_STATS is supported since v16 */
+ Assert(serverVersion >= 160000);
+ appendPQExpBuffer(sql, "%sSKIP_DATABASE_STATS", sep);
+ sep = comma;
+ }
+ if (vacopts->skip_locked)
+ {
+ /* SKIP_LOCKED is supported since v12 */
+ Assert(serverVersion >= 120000);
+ appendPQExpBuffer(sql, "%sSKIP_LOCKED", sep);
+ sep = comma;
+ }
+ if (vacopts->full)
+ {
+ appendPQExpBuffer(sql, "%sFULL", sep);
+ sep = comma;
+ }
+ if (vacopts->freeze)
+ {
+ appendPQExpBuffer(sql, "%sFREEZE", sep);
+ sep = comma;
+ }
+ if (vacopts->verbose)
+ {
+ appendPQExpBuffer(sql, "%sVERBOSE", sep);
+ sep = comma;
+ }
+ if (vacopts->and_analyze)
+ {
+ appendPQExpBuffer(sql, "%sANALYZE", sep);
+ sep = comma;
+ }
+ if (vacopts->parallel_workers >= 0)
+ {
+ /* PARALLEL is supported since v13 */
+ Assert(serverVersion >= 130000);
+ appendPQExpBuffer(sql, "%sPARALLEL %d", sep,
+ vacopts->parallel_workers);
+ sep = comma;
+ }
+ if (vacopts->buffer_usage_limit)
+ {
+ Assert(serverVersion >= 160000);
+ appendPQExpBuffer(sql, "%sBUFFER_USAGE_LIMIT '%s'", sep,
+ vacopts->buffer_usage_limit);
+ sep = comma;
+ }
+ if (sep != paren)
+ appendPQExpBufferChar(sql, ')');
+ }
+ else
+ {
+ if (vacopts->full)
+ appendPQExpBufferStr(sql, " FULL");
+ if (vacopts->freeze)
+ appendPQExpBufferStr(sql, " FREEZE");
+ if (vacopts->verbose)
+ appendPQExpBufferStr(sql, " VERBOSE");
+ if (vacopts->and_analyze)
+ appendPQExpBufferStr(sql, " ANALYZE");
+ }
+ }
+
+ appendPQExpBuffer(sql, " %s;", table);
+}
+
+/*
+ * Send a vacuum/analyze command to the server, returning after sending the
+ * command.
+ *
+ * Any errors during command execution are reported to stderr.
+ */
+static void
+run_vacuum_command(PGconn *conn, const char *sql, bool echo,
+ const char *table)
+{
+ bool status;
+
+ if (echo)
+ printf("%s\n", sql);
+
+ status = PQsendQuery(conn, sql) == 1;
+
+ if (!status)
+ {
+ if (table)
+ {
+ pg_log_error("vacuuming of table \"%s\" in database \"%s\" failed: %s",
+ table, PQdb(conn), PQerrorMessage(conn));
+ }
+ else
+ {
+ pg_log_error("vacuuming of database \"%s\" failed: %s",
+ PQdb(conn), PQerrorMessage(conn));
+ }
+ }
+}
+
+/*
+ * Returns a newly malloc'd version of 'src' with escaped single quotes and
+ * backslashes.
+ */
+char *
+escape_quotes(const char *src)
+{
+ char *result = escape_single_quotes_ascii(src);
+
+ if (!result)
+ pg_fatal("out of memory");
+ return result;
+}
diff --git a/src/bin/scripts/vacuuming.h b/src/bin/scripts/vacuuming.h
new file mode 100644
index 00000000000..021953e153a
--- /dev/null
+++ b/src/bin/scripts/vacuuming.h
@@ -0,0 +1,68 @@
+/*-------------------------------------------------------------------------
+ *
+ * vacuuming.h
+ * Common declarations for vacuuming.c
+ *
+ * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/scripts/vacuuming.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef VACUUMING_H
+#define VACUUMING_H
+
+#include "common.h"
+#include "fe_utils/connect_utils.h"
+#include "fe_utils/simple_list.h"
+
+/* For analyze-in-stages mode */
+#define ANALYZE_NO_STAGE -1
+#define ANALYZE_NUM_STAGES 3
+
+/* vacuum options controlled by user flags */
+typedef struct vacuumingOptions
+{
+ bool analyze_only;
+ bool verbose;
+ bool and_analyze;
+ bool full;
+ bool freeze;
+ bool disable_page_skipping;
+ bool skip_locked;
+ int min_xid_age;
+ int min_mxid_age;
+ int parallel_workers; /* >= 0 indicates user specified the
+ * parallel degree, otherwise -1 */
+ bool no_index_cleanup;
+ bool force_index_cleanup;
+ bool do_truncate;
+ bool process_main;
+ bool process_toast;
+ bool skip_database_stats;
+ char *buffer_usage_limit;
+ bool missing_stats_only;
+} vacuumingOptions;
+
+/* object filter options */
+typedef enum
+{
+ OBJFILTER_NONE = 0, /* no filter used */
+ OBJFILTER_ALL_DBS = (1 << 0), /* -a | --all */
+ OBJFILTER_DATABASE = (1 << 1), /* -d | --dbname */
+ OBJFILTER_TABLE = (1 << 2), /* -t | --table */
+ OBJFILTER_SCHEMA = (1 << 3), /* -n | --schema */
+ OBJFILTER_SCHEMA_EXCLUDE = (1 << 4), /* -N | --exclude-schema */
+} VacObjFilter;
+
+extern int vacuuming_main(ConnParams *cparams, const char *dbname,
+ const char *maintenance_db, vacuumingOptions *vacopts,
+ VacObjFilter objfilter, SimpleStringList *objects,
+ int tbl_count, bool analyze_in_stages,
+ int concurrentCons,
+ const char *progname, bool echo, bool quiet);
+
+extern char *escape_quotes(const char *src);
+
+#endif /* VACUUMING_H */
base-commit: e849bd551c323a384f2b14d20a1b7bfaa6127ed7
--
2.47.3
--52vaejy5wnlkvc5v
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
filename="v22-0002-Add-REPACK-command.patch"
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index eedc5c8..c4d5cb1 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -282,6 +284,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -701,6 +704,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -981,16 +985,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1003,8 +1028,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1923,6 +1948,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 4bcd4e9..03fbd97 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 3e8929a..db2a21d 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc--
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 6cc2acb..7dfc311 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -113,6 +113,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -310,6 +312,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -739,6 +742,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -1017,16 +1021,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1039,8 +1064,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1978,6 +2003,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 81efebc..21f1362 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index c1f4ab5..92abe13 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg15.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index a758e1a..d08b122 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -108,6 +108,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -200,6 +202,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -568,6 +571,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -921,16 +925,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -943,8 +968,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1374,6 +1399,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg17.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index ba9bbb6..74fc499 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -107,6 +107,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -199,6 +201,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -567,6 +570,7 @@ executeJsonPath(JsonPath *path, Jsonb *vars, Jsonb *json, bool throwErrors,
cxt.lastGeneratedObjectId = vars ? 2 : 1;
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenseOfErrors(&cxt) && !result)
@@ -920,16 +924,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -942,8 +967,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1373,6 +1398,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index eafb421..5e1bd19 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -792,6 +792,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index 8163fc6..4c62fe2 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -155,6 +155,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg16.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.
This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes. A similar pattern
in strict mode can also provoke very large memory allocation attempts.
Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
src/backend/utils/adt/jsonpath_exec.c | 47 +++++++++++++++++++---
.../src/test/regress/expected/jsonb_jsonpath.out | 40 ++++++++++++++++++
src/test/regress/sql/jsonb_jsonpath.sql | 11 +++++
3 files changed, 93 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c
index 9b7187e..21d21ea 100644
--- a/src/backend/utils/adt/jsonpath_exec.c
+++ b/src/backend/utils/adt/jsonpath_exec.c
@@ -115,6 +115,8 @@ typedef struct JsonPathExecContext
* ignored */
bool throwErrors; /* with "false" all suppressible errors are
* suppressed */
+ bool existsOnly; /* @? / jsonb_path_exists: may collapse
+ * redundant consecutive .** accessors */
bool useTz;
} JsonPathExecContext;
@@ -284,6 +286,7 @@ static JsonPathExecResult executeAnyItem(JsonPathExecContext *cxt,
JsonPathItem *jsp, JsonbContainer *jbc, JsonValueList *found,
uint32 level, uint32 first, uint32 last,
bool ignoreStructuralErrors, bool unwrapNext);
+static uint32 mergeAnyBound(uint32 a, uint32 b);
static JsonPathBool executePredicate(JsonPathExecContext *cxt,
JsonPathItem *pred, JsonPathItem *larg, JsonPathItem *rarg,
JsonbValue *jb, bool unwrapRightArg,
@@ -703,6 +706,7 @@ executeJsonPath(JsonPath *path, void *vars, JsonPathGetVarCallback getVar,
cxt.lastGeneratedObjectId = 1 + countVars(vars);
cxt.innermostArraySize = -1;
cxt.throwErrors = throwErrors;
+ cxt.existsOnly = (result == NULL);
cxt.useTz = useTz;
if (jspStrictAbsenceOfErrors(&cxt) && !result)
@@ -983,16 +987,37 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
case jpiAny:
{
- bool hasNext = jspGetNext(jsp, &elem);
+ JsonPathItem elem;
+ bool hasNext;
+ uint32 first;
+ uint32 last;
+
+ hasNext = jspGetNext(jsp, &elem);
+ first = jsp->content.anybounds.first;
+ last = jsp->content.anybounds.last;
+
+ /*
+ * Consecutive .** accessors are redundant for existence
+ * queries and multiply traversal cost.
+ */
+ if (cxt->existsOnly)
+ {
+ while (hasNext && elem.type == jpiAny)
+ {
+ first = mergeAnyBound(first, elem.content.anybounds.first);
+ last = mergeAnyBound(last, elem.content.anybounds.last);
+ hasNext = jspGetNext(&elem, &elem);
+ }
+ }
/* first try without any intermediate steps */
- if (jsp->content.anybounds.first == 0)
+ if (first == 0)
{
bool savedIgnoreStructuralErrors;
savedIgnoreStructuralErrors = cxt->ignoreStructuralErrors;
cxt->ignoreStructuralErrors = true;
- res = executeNextItem(cxt, jsp, &elem,
+ res = executeNextItem(cxt, jsp, hasNext ? &elem : NULL,
jb, found, true);
cxt->ignoreStructuralErrors = savedIgnoreStructuralErrors;
@@ -1005,8 +1030,8 @@ executeItemOptUnwrapTarget(JsonPathExecContext *cxt, JsonPathItem *jsp,
(cxt, hasNext ? &elem : NULL,
jb->val.binary.data, found,
1,
- jsp->content.anybounds.first,
- jsp->content.anybounds.last,
+ first,
+ last,
true, jspAutoUnwrap(cxt));
break;
}
@@ -1924,6 +1949,18 @@ executeNestedBoolItem(JsonPathExecContext *cxt, JsonPathItem *jsp,
return res;
}
+
+/*
+ * Merge level bounds of two consecutive .** accessors.
+ */
+static uint32
+mergeAnyBound(uint32 a, uint32 b)
+{
+ if (a == PG_UINT32_MAX || b == PG_UINT32_MAX)
+ return PG_UINT32_MAX;
+ return a + b;
+}
+
/*
* Implementation of several jsonpath nodes:
* - jpiAny (.** accessor),
diff --git a/src/test/regress/expected/jsonb_jsonpath.out b/src/test/regress/expected/jsonb_jsonpath.out
index 8cf6ecf..0bbad25 100644
--- a/src/test/regress/expected/jsonb_jsonpath.out
+++ b/src/test/regress/expected/jsonb_jsonpath.out
@@ -785,6 +785,46 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
t
(1 row)
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+ ?column?
+----------
+ t
+(1 row)
+
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+ ?column?
+----------
+ f
+(1 row)
+
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+ jsonb_path_exists
+-------------------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+ ?column?
+----------
+ t
+(1 row)
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
jsonb_path_query
------------------
diff --git a/src/test/regress/sql/jsonb_jsonpath.sql b/src/test/regress/sql/jsonb_jsonpath.sql
index acb508c..1d867d8 100644
--- a/src/test/regress/sql/jsonb_jsonpath.sql
+++ b/src/test/regress/sql/jsonb_jsonpath.sql
@@ -150,6 +150,17 @@ select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{0 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to last}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{1 to 2}.b ? ( @ > 0)';
select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**{2 to 3}.b ? ( @ > 0)';
+-- Redundant consecutive .** accessors are collapsed for existence queries
+-- (@? and jsonb_path_exists), avoiding multiplicative traversal cost.
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 0)';
+select jsonb '{"a": {"c": {"b": 1}}}' @? '$.**.**.b ? (@ > 99)';
+select jsonb_path_exists('{"a": {"c": {"b": 1}}}', '$.**.**.b ? (@ > 0)');
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'lax $.**.**.**.**';
+select ('[' || repeat('[', 50) || '0' || repeat(']', 50) || ']')::jsonb
+ @? 'strict $.**.**.**';
+
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.x))');
select jsonb_path_query('{"g": {"x": 2}}', '$.g ? (exists (@.y))');
--
2.47.3
--MP_/BlgiDE/t55y8Vb7V2uvNybc
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename=0001-collapse-consecutive-jsonpath-any-pg18.patch
^ permalink raw reply [nested|flat] 942+ messages in thread
* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-07-06 18:50 Andrey Rachitskiy <[email protected]>
0 siblings, 0 replies; 942+ messages in thread
From: Andrey Rachitskiy @ 2026-07-06 18:50 UTC (permalink / raw)
To: PostgreSQL Hackers <[email protected]>; +Cc: Nikolay Shaplov <[email protected]>; Amit Langote <[email protected]>; Andrey Borodin <[email protected]>
Hi, Hackers!
When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in
executeAnyItem(). A chain of k such accessors can cost O(N^k) on a
document with N nodes, even though for existence semantics it is
equivalent to a single .** with merged level bounds.
Background
----------
We originally reported this as BUG #19362 [1], with a follow-up
analysis [2]. The original report used a fuzzer-generated sql
statement; the follow-up gave a clearer reproduction. For example, on
a JSON array nested 1000 levels deep:
SELECT data @? '$.**.**.**.**' FROM test_json; -- ~0.5 ms
SELECT data @? '$.**.**.**.**.*' FROM test_json; -- >23 min
(cancelled)
Andrey Borodin replied that this looks like a performance optimization
opportunity rather than a bug, and asked for a more realistic example of
what a user might want but not get in reasonable time [3]. We agree,
and are sending this to pgsql-hackers.
A developer searching semi-structured JSON (nested categories, comment
threads, task lists) might use @? / jsonb_path_exists with paths such as
$.**.b ? (@ > 0) — "does key b exist anywhere, with this predicate?"
Templates, copy-paste, or auto-generated paths can accidentally
accumulate redundant .** segments (.**.**.b), which is semantically the
same as $.**.b for existence checks but much slower.
If an application accepts user-supplied jsonpath for @?, a path with
many consecutive .** operators also becomes an easy DoS vector: no
special privileges beyond the ability to run a query.
Proposal
--------
Collapse consecutive jpiAny nodes at execution time for existence
queries (@? and jsonb_path_exists): merge level bounds and perform a
single executeAnyItem() pass (.** {a,b} .** {c,d} -> .** {a+c,b+d}).
For existence checks this bounds the cost of a k-deep .** chain to
O(N) instead of O(N^k), so paths that previously hung the backend for
many minutes on the BUG #19362 reproduction now finish in under a
millisecond. That closes a practical DoS vector for applications that
pass user-supplied jsonpath to @?.
This patch intentionally does NOT change jsonb_path_query or @@: those
functions collect item sequences, and consecutive .** affects result
multiplicity (e.g. lax $.**.** vs $.**). The optimization is gated on
existsOnly (result == NULL in executeJsonPath()).
jsonb_jsonpath regress tests are included.
Backpatch-through: 15.
Separate patches for REL_15_STABLE through master are attached.
[1] https://postgr.es/m/[email protected]
[2] https://postgr.es/m/[email protected]
[3]
https://postgr.es/m/[email protected]
Author: Andrey Rachitskiy <[email protected]>
Reported-by: Nikolay Shaplov <[email protected]>
Tested-on: REL_15_STABLE .. master
--
Regards,
Andrey Rachitskiy
^ permalink raw reply [nested|flat] 942+ messages in thread
end of thread, other threads:[~2026-07-06 18:50 UTC | newest]
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2025-09-25 12:58 [PATCH v22 1/2] Split vacuumdb to create vacuuming.c/h Álvaro Herrera <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
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2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
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2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
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2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
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2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-06-18 20:30 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
2026-07-06 18:50 [PATCH] Collapse consecutive .** accessors for jsonpath exists queries Andrey Rachitskiy <[email protected]>
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