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[PATCH v43 4/7] Use BulkInsertState when copying data to the new heap.
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* [PATCH v43 4/7] Use BulkInsertState when copying data to the new heap.
@ 2026-03-11 14:20  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Antonin Houska @ 2026-03-11 14:20 UTC (permalink / raw)

It should make the copying more efficient. Besides that, buffer access
strategy is involved this way.

This diff reverts the changes done in previous parts of the series to
reform_and_rewrite_tuple() and introduces a separate function
heap_insert_for_repack().
---
 src/backend/access/heap/heapam_handler.c | 110 +++++++++++++++--------
 1 file changed, 72 insertions(+), 38 deletions(-)

diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 618b831e8eb..065bb233fe2 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -50,6 +50,11 @@
 static void reform_and_rewrite_tuple(HeapTuple tuple,
 									 Relation OldHeap, Relation NewHeap,
 									 Datum *values, bool *isnull, RewriteState rwstate);
+static void heap_insert_for_repack(HeapTuple tuple, Relation OldHeap,
+								   Relation NewHeap, Datum *values, bool *isnull,
+								   BulkInsertState bistate);
+static HeapTuple reform_tuple(HeapTuple tuple, Relation OldHeap,
+							  Relation NewHeap, Datum *values, bool *isnull);
 
 static bool SampleHeapTupleVisible(TableScanDesc scan, Buffer buffer,
 								   HeapTuple tuple,
@@ -702,6 +707,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 								 double *tups_recently_dead)
 {
 	RewriteState rwstate = NULL;
+	BulkInsertState	bistate = NULL;
 	IndexScanDesc indexScan;
 	TableScanDesc tableScan;
 	HeapScanDesc heapScan;
@@ -737,6 +743,8 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 	if (!concurrent)
 		rwstate = begin_heap_rewrite(OldHeap, NewHeap, OldestXmin,
 									 *xid_cutoff, *multi_cutoff);
+	else
+		bistate = GetBulkInsertState();
 
 
 	/* Set up sorting if wanted */
@@ -966,8 +974,12 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 			};
 			int64		ct_val[2];
 
-			reform_and_rewrite_tuple(tuple, OldHeap, NewHeap,
-									 values, isnull, rwstate);
+			if (!concurrent)
+				reform_and_rewrite_tuple(tuple, OldHeap, NewHeap,
+										 values, isnull, rwstate);
+			else
+				heap_insert_for_repack(tuple, OldHeap, NewHeap,
+									   values, isnull, bistate);
 
 			/*
 			 * In indexscan mode and also VACUUM FULL, report increase in
@@ -1015,10 +1027,15 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 				break;
 
 			n_tuples += 1;
-			reform_and_rewrite_tuple(tuple,
-									 OldHeap, NewHeap,
-									 values, isnull,
-									 rwstate);
+			if (!concurrent)
+				reform_and_rewrite_tuple(tuple,
+										 OldHeap, NewHeap,
+										 values, isnull,
+										 rwstate);
+			else
+				heap_insert_for_repack(tuple, OldHeap, NewHeap,
+									   values, isnull, bistate);
+
 			/* Report n_tuples */
 			pgstat_progress_update_param(PROGRESS_REPACK_HEAP_TUPLES_INSERTED,
 										 n_tuples);
@@ -1030,6 +1047,8 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
 	/* Write out any remaining tuples, and fsync if needed */
 	if (rwstate)
 		end_heap_rewrite(rwstate);
+	if (bistate)
+		FreeBulkInsertState(bistate);
 
 	/* Clean up */
 	pfree(values);
@@ -2422,56 +2441,71 @@ heapam_scan_sample_next_tuple(TableScanDesc scan, SampleScanState *scanstate,
  * SET WITHOUT OIDS.
  *
  * So, we must reconstruct the tuple from component Datums.
- *
- * If rwstate=NULL, use simple_heap_insert() instead of rewriting - in that
- * case we still need to deform/form the tuple. TODO Shouldn't we rename the
- * function, as might not do any rewrite?
  */
 static void
 reform_and_rewrite_tuple(HeapTuple tuple,
 						 Relation OldHeap, Relation NewHeap,
 						 Datum *values, bool *isnull, RewriteState rwstate)
+{
+	HeapTuple       copiedTuple;
+
+	copiedTuple = reform_tuple(tuple, OldHeap, NewHeap, values, isnull);
+
+	/* The heap rewrite module does the rest */
+	rewrite_heap_tuple(rwstate, tuple, copiedTuple);
+
+	heap_freetuple(copiedTuple);
+}
+
+/*
+ * Insert tuple when processing REPACK CONCURRENTLY.
+ *
+ * rewriteheap.c is not used in the CONCURRENTLY case because it'd be
+ * difficult to do the same in the catch-up phase (as the logical
+ * decoding does not provide us with sufficient visibility
+ * information). Thus we must use heap_insert() both during the
+ * catch-up and here.
+ *
+ * We pass the NO_LOGICAL flag to heap_insert() in order to skip logical
+ * decoding: as soon as REPACK CONCURRENTLY swaps the relation files, it drops
+ * this relation, so no logical replication subscription should need the data.
+ *
+ * BulkInsertState is used because many tuples are inserted in the typical
+ * case.
+ */
+static void
+heap_insert_for_repack(HeapTuple tuple, Relation OldHeap, Relation NewHeap,
+					   Datum *values, bool *isnull, BulkInsertState bistate)
+{
+	tuple = reform_tuple(tuple, OldHeap, NewHeap, values, isnull);
+
+	heap_insert(NewHeap, tuple, GetCurrentCommandId(true),
+				HEAP_INSERT_NO_LOGICAL, bistate);
+
+	heap_freetuple(tuple);
+}
+
+/*
+ * Deform tuple, set values of dropped columns to NULL, form a new tuple and
+ * return it.
+ */
+static HeapTuple
+reform_tuple(HeapTuple tuple, Relation OldHeap, Relation NewHeap,
+			 Datum *values, bool *isnull)
 {
 	TupleDesc	oldTupDesc = RelationGetDescr(OldHeap);
 	TupleDesc	newTupDesc = RelationGetDescr(NewHeap);
-	HeapTuple	copiedTuple;
 	int			i;
 
 	heap_deform_tuple(tuple, oldTupDesc, values, isnull);
 
-	/* Be sure to null out any dropped columns */
 	for (i = 0; i < newTupDesc->natts; i++)
 	{
 		if (TupleDescCompactAttr(newTupDesc, i)->attisdropped)
 			isnull[i] = true;
 	}
 
-	copiedTuple = heap_form_tuple(newTupDesc, values, isnull);
-
-	if (rwstate)
-		/* The heap rewrite module does the rest */
-		rewrite_heap_tuple(rwstate, tuple, copiedTuple);
-	else
-	{
-		/*
-		 * Insert tuple when processing REPACK CONCURRENTLY.
-		 *
-		 * rewriteheap.c is not used in the CONCURRENTLY case because it'd be
-		 * difficult to do the same in the catch-up phase (as the logical
-		 * decoding does not provide us with sufficient visibility
-		 * information). Thus we must use heap_insert() both during the
-		 * catch-up and here.
-		 *
-		 * The following is like simple_heap_insert() except that we pass the
-		 * flag to skip logical decoding: as soon as REPACK CONCURRENTLY swaps
-		 * the relation files, it drops this relation, so no logical
-		 * replication subscription should need the data.
-		 */
-		heap_insert(NewHeap, copiedTuple, GetCurrentCommandId(true),
-					HEAP_INSERT_NO_LOGICAL, NULL);
-	}
-
-	heap_freetuple(copiedTuple);
+	return heap_form_tuple(newTupDesc, values, isnull);
 }
 
 /*
-- 
2.47.3


--nzintiedl6o4kcyp
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
	filename="v43-0005-Fix-crash-caused-by-involuntary-decoding-of-unre.patch"



^ permalink  raw  reply  [nested|flat] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread

* [PATCH] Collapse consecutive .** accessors for jsonpath exists queries
@ 2026-06-18 20:30  Andrey Rachitskiy <[email protected]>
  0 siblings, 0 replies; 1027+ messages in thread

From: Andrey Rachitskiy @ 2026-06-18 20:30 UTC (permalink / raw)

When a jsonpath expression contains multiple consecutive .** (jpiAny)
accessors, each one triggers a full subtree traversal in executeAnyItem().
k consecutive .** operators can degrade performance to O(N^k) on a document
with N nodes, even though a chain like $.**.**.** is redundant for existence
semantics and equivalent to a single $.** with merged level bounds.

This was reported as a performance problem when expressions such as
$.**.**.**.**.* are evaluated with @? against deeply nested JSON: the same
query without the trailing .* completes in sub-millisecond time, while the
form with redundant .** segments can run for many minutes.  A similar pattern
in strict mode can also provoke very large memory allocation attempts.

Collapse consecutive jpiAny nodes at execution time for existence queries
(@? and jsonb_path_exists), merging their level bounds and performing a
single executeAnyItem() pass.

Author: Andrey Rachitskiy <[email protected]>
Reported-by: Andrey Rachitskiy <[email protected]>
Backpatch-through: 15
---
 src/backend/utils/adt/jsonpath_exec.c     | 47 +++++++++++++++++++---
 .../src/test/regress/expected/jsonb_jsonpath.out   | 40 ++++++++++++++++++
 src/test/regress/sql/jsonb_jsonpath.sql   | 11 +++++
 3 files 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] 1027+ messages in thread