From 3fcd83072f205c7d94453c806a78925cd4658dde Mon Sep 17 00:00:00 2001 From: "okbob@github.com" Date: Thu, 6 Jul 2023 08:29:21 +0200 Subject: [PATCH 02/20] Storage for session variables and SQL interface Session variables are stored in session memory in a dedicated hash table. They are set by the LET command and read by the SELECT command. The access rights should be checked. The identifiers of session variables should always be shadowed by possible column identifiers: we don't want to break an application by creating some badly named session variable. The limits of this patch (solved by other patches): - session variables block parallel execution - session variables blocks simple expression evaluation (in plpgsql) - SQL functions with session variables are not inlined - CALL statement is not supported (usage of direct access to express executor) - EXECUTE statement is not supported (usage of direct access to express executor) - memory used by dropped session variables is not released Implementations of EXPLAIN LET and PREPARE LET statements are in separate patches (for better readability) --- doc/src/sgml/catalogs.sgml | 13 + doc/src/sgml/ddl.sgml | 32 + doc/src/sgml/event-trigger.sgml | 24 + doc/src/sgml/parallel.sgml | 6 + doc/src/sgml/plpgsql.sgml | 14 + doc/src/sgml/ref/allfiles.sgml | 1 + doc/src/sgml/ref/alter_variable.sgml | 1 + doc/src/sgml/ref/create_variable.sgml | 1 + doc/src/sgml/ref/drop_variable.sgml | 1 + doc/src/sgml/ref/let.sgml | 96 ++ doc/src/sgml/reference.sgml | 1 + src/backend/catalog/dependency.c | 5 + src/backend/catalog/namespace.c | 315 ++++++ src/backend/catalog/pg_variable.c | 2 + src/backend/commands/Makefile | 1 + src/backend/commands/meson.build | 1 + src/backend/commands/prepare.c | 8 + src/backend/commands/session_variable.c | 571 +++++++++++ src/backend/executor/Makefile | 1 + src/backend/executor/execExpr.c | 36 + src/backend/executor/execMain.c | 57 ++ src/backend/executor/meson.build | 1 + src/backend/executor/svariableReceiver.c | 201 ++++ src/backend/nodes/nodeFuncs.c | 10 + src/backend/optimizer/plan/planner.c | 9 + src/backend/optimizer/plan/setrefs.c | 135 ++- src/backend/optimizer/prep/prepjointree.c | 3 + src/backend/optimizer/util/clauses.c | 35 +- src/backend/parser/analyze.c | 264 ++++- src/backend/parser/gram.y | 49 +- src/backend/parser/parse_agg.c | 9 + src/backend/parser/parse_expr.c | 220 ++++- src/backend/parser/parse_func.c | 2 + src/backend/tcop/dest.c | 7 + src/backend/tcop/pquery.c | 3 + src/backend/tcop/utility.c | 16 + src/backend/utils/adt/ruleutils.c | 46 + src/backend/utils/cache/plancache.c | 41 +- src/backend/utils/fmgr/fmgr.c | 10 +- src/bin/psql/tab-complete.c | 12 +- src/include/catalog/namespace.h | 2 + src/include/catalog/pg_variable.h | 8 + src/include/commands/session_variable.h | 32 + src/include/executor/execdesc.h | 4 + src/include/executor/svariableReceiver.h | 22 + src/include/nodes/execnodes.h | 16 + src/include/nodes/parsenodes.h | 17 + src/include/nodes/pathnodes.h | 5 + src/include/nodes/plannodes.h | 4 +- src/include/nodes/primnodes.h | 6 + src/include/optimizer/planmain.h | 2 + src/include/parser/kwlist.h | 1 + src/include/parser/parse_node.h | 3 + src/include/tcop/cmdtaglist.h | 1 + src/include/tcop/dest.h | 1 + src/pl/plpgsql/src/pl_exec.c | 3 +- .../regress/expected/session_variables.out | 922 ++++++++++++++++++ src/test/regress/sql/session_variables.sql | 637 ++++++++++++ src/tools/pgindent/typedefs.list | 5 + 59 files changed, 3928 insertions(+), 23 deletions(-) create mode 100644 doc/src/sgml/ref/let.sgml create mode 100644 src/backend/commands/session_variable.c create mode 100644 src/backend/executor/svariableReceiver.c create mode 100644 src/include/commands/session_variable.h create mode 100644 src/include/executor/svariableReceiver.h diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index de122e543f7..ac3b04ff912 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9777,6 +9777,19 @@ SCRAM-SHA-256$<iteration count>:&l + + + varcreate_lsn XLogRecPtr + + + LSN of the transaction where the variable was created. + varcreate_lsn and + oid together form the all-time unique + identifier (oid alone is not enough, since + object identifiers can get reused). + + + varname name diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml index df6e1b424c7..7eee2a8e803 100644 --- a/doc/src/sgml/ddl.sgml +++ b/doc/src/sgml/ddl.sgml @@ -5279,6 +5279,38 @@ EXPLAIN SELECT count(*) FROM measurement WHERE logdate >= DATE '2008-01-01'; VARIABLE command. + + The value of a session variable is set with the SQL statement + LET. The value of a session variable can be retrieved + with the SQL statement SELECT. + +CREATE VARIABLE var1 AS date; +LET var1 = current_date; +SELECT var1; + + + or + + +CREATE VARIABLE public.current_user_id AS integer; +GRANT READ ON VARIABLE public.current_user_id TO PUBLIC; +LET current_user_id = (SELECT id FROM users WHERE usename = session_user); +SELECT current_user_id; + + + + + The value of a session variable is local to the current session. Retrieving + a variable's value returns a NULL, unless its value has + been set to something else in the current session using the + LET command. Session variables are not transactional: + any changes made to the value of a session variable in a transaction won't + be undone if the transaction is rolled back (just like variables in + procedural languages). Session variables themselves are persistent, but + their values are neither persistent nor shared (like the content of + temporary tables). + + Inside a query or an expression, a session variable can be shadowed by a column with the same name. Similarly, the diff --git a/doc/src/sgml/event-trigger.sgml b/doc/src/sgml/event-trigger.sgml index 15b2af99dca..578b97afeef 100644 --- a/doc/src/sgml/event-trigger.sgml +++ b/doc/src/sgml/event-trigger.sgml @@ -432,6 +432,14 @@ - + + ALTER VARIABLE + X + X + - + - + + ALTER VIEW X @@ -728,6 +736,14 @@ - + + CREATE VARIABLE + X + X + - + - + + CREATE VIEW X @@ -1024,6 +1040,14 @@ - + + DROP VARIABLE + X + X + X + - + + DROP VIEW X diff --git a/doc/src/sgml/parallel.sgml b/doc/src/sgml/parallel.sgml index 4b3df7c2f8d..3936a62c5f9 100644 --- a/doc/src/sgml/parallel.sgml +++ b/doc/src/sgml/parallel.sgml @@ -521,6 +521,12 @@ EXPLAIN SELECT * FROM pgbench_accounts WHERE filler LIKE '%x%'; Plan nodes that reference a correlated SubPlan. + + + + Plan nodes that use a session variable. + + diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 78e4983139b..bfbff9ab74e 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -6034,6 +6034,20 @@ $$ LANGUAGE plpgsql STRICT IMMUTABLE; + + + <command>Packages and package variables</command> + + + The PL/pgSQL language has no packages, and + therefore no package variables or package constants. + You can consider translating an Oracle package into a schema in + PostgreSQL. Package functions and procedures + would then become functions and procedures in that schema, and package + variables could be translated to session variables in that schema. + (see ). + + diff --git a/doc/src/sgml/ref/allfiles.sgml b/doc/src/sgml/ref/allfiles.sgml index 2f67de3e21b..cc3bd5ab540 100644 --- a/doc/src/sgml/ref/allfiles.sgml +++ b/doc/src/sgml/ref/allfiles.sgml @@ -158,6 +158,7 @@ Complete list of usable sgml source files in this directory. + diff --git a/doc/src/sgml/ref/alter_variable.sgml b/doc/src/sgml/ref/alter_variable.sgml index d87570e7d8b..d2036351e53 100644 --- a/doc/src/sgml/ref/alter_variable.sgml +++ b/doc/src/sgml/ref/alter_variable.sgml @@ -173,6 +173,7 @@ ALTER VARIABLE boo SET SCHEMA private; + diff --git a/doc/src/sgml/ref/create_variable.sgml b/doc/src/sgml/ref/create_variable.sgml index ec165ab96fc..05bf67e3411 100644 --- a/doc/src/sgml/ref/create_variable.sgml +++ b/doc/src/sgml/ref/create_variable.sgml @@ -145,6 +145,7 @@ SELECT var1; + diff --git a/doc/src/sgml/ref/drop_variable.sgml b/doc/src/sgml/ref/drop_variable.sgml index 5bdb3560f0b..67988b5fcd8 100644 --- a/doc/src/sgml/ref/drop_variable.sgml +++ b/doc/src/sgml/ref/drop_variable.sgml @@ -111,6 +111,7 @@ DROP VARIABLE var1; + diff --git a/doc/src/sgml/ref/let.sgml b/doc/src/sgml/ref/let.sgml new file mode 100644 index 00000000000..f6640576bee --- /dev/null +++ b/doc/src/sgml/ref/let.sgml @@ -0,0 +1,96 @@ + + + + + LET + + + + session variable + changing + + + + LET + 7 + SQL - Language Statements + + + + LET + change a session variable's value + + + + +LET session_variable = sql_expression + + + + + Description + + + The LET command assigns a value to the specified session + variable. + + + + + + Parameters + + + + session_variable + + + The name of the session variable. + + + + + + sql_expression + + + An arbitrary SQL expression. The result must be of a data type that can + be cast to the type of the session variable in an assignment. + + + + + + + + Example: + +CREATE VARIABLE myvar AS integer; +LET myvar = 10; +LET myvar = (SELECT sum(val) FROM tab); + + + + + + Compatibility + + + The LET is a PostgreSQL + extension. + + + + + See Also + + + + + + + + diff --git a/doc/src/sgml/reference.sgml b/doc/src/sgml/reference.sgml index 25578f3946c..13e4adc5df3 100644 --- a/doc/src/sgml/reference.sgml +++ b/doc/src/sgml/reference.sgml @@ -186,6 +186,7 @@ &grant; &importForeignSchema; &insert; + &let; &listen; &load; &lock; diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c index c9d686665de..148719e490e 100644 --- a/src/backend/catalog/dependency.c +++ b/src/backend/catalog/dependency.c @@ -1864,6 +1864,11 @@ find_expr_references_walker(Node *node, { Param *param = (Param *) node; + /* a variable parameter depends on the session variable */ + if (param->paramkind == PARAM_VARIABLE) + add_object_address(VariableRelationId, param->paramvarid, 0, + context->addrs); + /* A parameter must depend on the parameter's datatype */ add_object_address(TypeRelationId, param->paramtype, 0, context->addrs); diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c index fd994c92d4f..375fea5dae8 100644 --- a/src/backend/catalog/namespace.c +++ b/src/backend/catalog/namespace.c @@ -3397,6 +3397,321 @@ LookupVariable(const char *nspname, return varoid; } +/* + * The input list contains names with indirection expressions used as the left + * part of LET statement. The following routine returns a new list with only + * initial strings (names) - without indirection expressions. + */ +List * +NamesFromList(List *names) +{ + ListCell *l; + List *result = NIL; + + foreach(l, names) + { + Node *n = lfirst(l); + + if (IsA(n, String)) + { + result = lappend(result, n); + } + else + break; + } + + return result; +} + +/* ----- + * IdentifyVariable - try to find a variable from a list of identifiers + * + * Returns the OID of the variable found, or InvalidOid. + * + * "names" is a list of up to four identifiers; possible meanings are: + * - variable (searched on the search_path) + * - schema.variable + * - variable.attribute (searched on the search_path) + * - schema.variable.attribute + * - database.schema.variable + * - database.schema.variable.attribute + * + * If there is more than one way to identify a variable, "not_unique" will be + * set to true. + * + * Unless "noerror" is true, an error is raised if there are more than four + * identifiers in the list, or if the named database is not the current one. + * This is useful if we want to identify a shadowed variable. + * + * If an attribute is identified, it is stored in "attrname", otherwise the + * parameter is set to NULL. + * + * The identified session variable will be locked with an AccessShareLock. + * ----- + */ +Oid +IdentifyVariable(List *names, char **attrname, bool *not_unique, bool noerror) +{ + Oid varid = InvalidOid; + Oid old_varid = InvalidOid; + uint64 inval_count; + bool retry = false; + + /* + * DDL operations can change the results of a name lookup. Since all such + * operations will generate invalidation messages, we keep track of + * whether any such messages show up while we're performing the operation, + * and retry until either (1) no more invalidation messages show up or (2) + * the answer doesn't change. + */ + for (;;) + { + Node *field1 = NULL; + Node *field2 = NULL; + Node *field3 = NULL; + Node *field4 = NULL; + char *a = NULL; + char *b = NULL; + char *c = NULL; + char *d = NULL; + Oid varoid_without_attr = InvalidOid; + Oid varoid_with_attr = InvalidOid; + + *not_unique = false; + *attrname = NULL; + varid = InvalidOid; + + inval_count = SharedInvalidMessageCounter; + + switch (list_length(names)) + { + case 1: + field1 = linitial(names); + + Assert(IsA(field1, String)); + + varid = LookupVariable(NULL, strVal(field1), true); + break; + + case 2: + field1 = linitial(names); + field2 = lsecond(names); + + Assert(IsA(field1, String)); + a = strVal(field1); + + if (IsA(field2, String)) + { + /* when both fields are of string type */ + b = strVal(field2); + + /* + * a.b can mean "schema"."variable" or "variable"."field". + * Check both variants, and returns InvalidOid with + * not_unique flag, when both interpretations are + * possible. + */ + varoid_without_attr = LookupVariable(a, b, true); + varoid_with_attr = LookupVariable(NULL, a, true); + } + else + { + /* the last field of list can be star too */ + Assert(IsA(field2, A_Star)); + + /* + * In this case, the field1 should be variable name. But + * direct unboxing of composite session variables is not + * supported now, and then we don't need to try lookup + * related variable. + * + * Unboxing is supported by syntax (var).* + */ + return InvalidOid; + } + + if (OidIsValid(varoid_without_attr) && OidIsValid(varoid_with_attr)) + { + *not_unique = true; + varid = varoid_without_attr; + } + else if (OidIsValid(varoid_without_attr)) + { + varid = varoid_without_attr; + } + else if (OidIsValid(varoid_with_attr)) + { + *attrname = b; + varid = varoid_with_attr; + } + break; + + case 3: + { + bool field1_is_catalog = false; + + field1 = linitial(names); + field2 = lsecond(names); + field3 = lthird(names); + + Assert(IsA(field1, String)); + Assert(IsA(field2, String)); + + a = strVal(field1); + b = strVal(field2); + + if (IsA(field3, String)) + { + c = strVal(field3); + + /* + * a.b.c can mean catalog.schema.variable or + * schema.variable.field. + * + * Check both variants, and set not_unique flag, when + * both interpretations are possible. + * + * When third node is star, only possible + * interpretation is schema.variable.*, but this + * pattern is not supported now. + */ + varoid_with_attr = LookupVariable(a, b, true); + + /* + * check pattern catalog.schema.variable only when + * there is possibility to success. + */ + if (strcmp(a, get_database_name(MyDatabaseId)) == 0) + { + field1_is_catalog = true; + varoid_without_attr = LookupVariable(b, c, true); + } + } + else + { + Assert(IsA(field3, A_Star)); + return InvalidOid; + } + + if (OidIsValid(varoid_without_attr) && OidIsValid(varoid_with_attr)) + { + *not_unique = true; + varid = varoid_without_attr; + } + else if (OidIsValid(varoid_without_attr)) + { + varid = varoid_without_attr; + } + else if (OidIsValid(varoid_with_attr)) + { + *attrname = c; + varid = varoid_with_attr; + } + + /* + * When we didn't find variable, we can (when it is + * allowed) raise cross-database reference error. + */ + if (!OidIsValid(varid) && !noerror && !field1_is_catalog) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cross-database references are not implemented: %s", + NameListToString(names)))); + } + break; + + case 4: + { + field1 = linitial(names); + field2 = lsecond(names); + field3 = lthird(names); + field4 = lfourth(names); + + Assert(IsA(field1, String)); + Assert(IsA(field2, String)); + Assert(IsA(field3, String)); + + a = strVal(field1); + b = strVal(field2); + c = strVal(field3); + + /* + * In this case, "a" is used as catalog name - check it. + */ + if (strcmp(a, get_database_name(MyDatabaseId)) != 0) + { + if (!noerror) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cross-database references are not implemented: %s", + NameListToString(names)))); + } + + if (IsA(field4, String)) + { + d = strVal(field4); + } + else + { + Assert(IsA(field4, A_Star)); + return InvalidOid; + } + + *attrname = d; + varid = LookupVariable(b, c, true); + } + break; + + default: + if (!noerror) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("improper qualified name (too many dotted names): %s", + NameListToString(names)))); + return InvalidOid; + } + + /* + * If, upon retry, we get back the same OID we did last time, then the + * invalidation messages we processed did not change the final answer. + * So we're done. + * + * If we got a different OID, we've locked the variable that used to + * have this name rather than the one that does now. So release the + * lock. + */ + if (retry) + { + if (old_varid == varid) + break; + + if (OidIsValid(old_varid)) + UnlockDatabaseObject(VariableRelationId, old_varid, 0, AccessShareLock); + } + + /* + * Lock the variable. This will also accept any pending invalidation + * messages. If we got back InvalidOid, indicating not found, then + * there's nothing to lock, but we accept invalidation messages + * anyway, to flush any negative catcache entries that may be + * lingering. + */ + if (!OidIsValid(varid)) + AcceptInvalidationMessages(); + else if (OidIsValid(varid)) + LockDatabaseObject(VariableRelationId, varid, 0, AccessShareLock); + + if (inval_count == SharedInvalidMessageCounter) + break; + + retry = true; + old_varid = varid; + varid = InvalidOid; + } + + return varid; +} + /* * DeconstructQualifiedName * Given a possibly-qualified name expressed as a list of String nodes, diff --git a/src/backend/catalog/pg_variable.c b/src/backend/catalog/pg_variable.c index e3a861c8cba..ef89594a268 100644 --- a/src/backend/catalog/pg_variable.c +++ b/src/backend/catalog/pg_variable.c @@ -26,6 +26,7 @@ #include "parser/parse_type.h" #include "utils/builtins.h" #include "utils/lsyscache.h" +#include "utils/pg_lsn.h" #include "utils/syscache.h" static ObjectAddress create_variable(const char *varName, @@ -101,6 +102,7 @@ create_variable(const char *varName, varid = GetNewOidWithIndex(rel, VariableOidIndexId, Anum_pg_variable_oid); values[Anum_pg_variable_oid - 1] = ObjectIdGetDatum(varid); + values[Anum_pg_variable_varcreate_lsn - 1] = LSNGetDatum(GetXLogInsertRecPtr()); values[Anum_pg_variable_varname - 1] = NameGetDatum(&varname); values[Anum_pg_variable_varnamespace - 1] = ObjectIdGetDatum(varNamespace); values[Anum_pg_variable_vartype - 1] = ObjectIdGetDatum(varType); diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile index cede90c3b98..59a6340a85e 100644 --- a/src/backend/commands/Makefile +++ b/src/backend/commands/Makefile @@ -50,6 +50,7 @@ OBJS = \ schemacmds.o \ seclabel.o \ sequence.o \ + session_variable.o \ statscmds.o \ subscriptioncmds.o \ tablecmds.o \ diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build index 7549be5dc3b..86da8105146 100644 --- a/src/backend/commands/meson.build +++ b/src/backend/commands/meson.build @@ -38,6 +38,7 @@ backend_sources += files( 'schemacmds.c', 'seclabel.c', 'sequence.c', + 'session_variable.c', 'statscmds.c', 'subscriptioncmds.c', 'tablecmds.c', diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c index 07257d4db94..719e63fe823 100644 --- a/src/backend/commands/prepare.c +++ b/src/backend/commands/prepare.c @@ -338,6 +338,14 @@ EvaluateParams(ParseState *pstate, PreparedStatement *pstmt, List *params, i++; } + /* + * The arguments of EXECUTE are evaluated by a direct expression + * executor call. This mode doesn't support session variables yet. + * It will be enabled later. + */ + if (pstate->p_hasSessionVariables) + elog(ERROR, "session variable cannot be used as an argument"); + /* Prepare the expressions for execution */ exprstates = ExecPrepareExprList(params, estate); diff --git a/src/backend/commands/session_variable.c b/src/backend/commands/session_variable.c new file mode 100644 index 00000000000..548d9835c0d --- /dev/null +++ b/src/backend/commands/session_variable.c @@ -0,0 +1,571 @@ +/*------------------------------------------------------------------------- + * + * session_variable.c + * session variable creation/manipulation commands + * + * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/commands/session_variable.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "catalog/pg_variable.h" +#include "commands/session_variable.h" +#include "executor/svariableReceiver.h" +#include "funcapi.h" +#include "miscadmin.h" +#include "rewrite/rewriteHandler.h" +#include "storage/lmgr.h" +#include "storage/proc.h" +#include "tcop/tcopprot.h" +#include "utils/builtins.h" +#include "utils/datum.h" +#include "utils/inval.h" +#include "utils/lsyscache.h" +#include "utils/snapmgr.h" +#include "utils/syscache.h" + +/* + * The values of session variables are stored in the backend's private memory + * in the dedicated memory context SVariableMemoryContext in binary format. + * They are stored in the "sessionvars" hash table, whose key is the OID of the + * variable. However, the OID is not good enough to identify a session + * variable: concurrent sessions could drop the session variable and create a + * new one, which could be assigned the same OID. To ensure that the values + * stored in memory and the catalog definition match, we also keep track of + * the "create_lsn". Before any access to the variable values, we need to + * check if the LSN stored in memory matches the LSN in the catalog. If there + * is a mismatch between the LSNs, or if the OID is not present in pg_variable + * at all, the value stored in memory is released. + */ +typedef struct SVariableData +{ + Oid varid; /* pg_variable OID of the variable (hash key) */ + XLogRecPtr create_lsn; + + bool isnull; + Datum value; + + Oid typid; + int16 typlen; + bool typbyval; + + bool is_domain; + + /* + * domain_check_extra holds cached domain metadata. This "extra" is + * usually stored in fn_mcxt. We do not have access to that memory context + * for session variables, but we can use TopTransactionContext instead. + * A fresh value is forced when we detect we are in a different transaction + * (the local transaction ID differs from domain_check_extra_lxid). + */ + void *domain_check_extra; + LocalTransactionId domain_check_extra_lxid; + + /* + * Stored value and type description can be outdated when we receive a + * sinval message. We then have to check if the stored data are still + * trustworthy. + */ + bool is_valid; + + uint32 hashvalue; /* used for pairing sinval message */ +} SVariableData; + +typedef SVariableData *SVariable; + +static HTAB *sessionvars = NULL; /* hash table for session variables */ + +static MemoryContext SVariableMemoryContext = NULL; + +/* + * Callback function for session variable invalidation. + */ +static void +pg_variable_cache_callback(Datum arg, int cacheid, uint32 hashvalue) +{ + HASH_SEQ_STATUS status; + SVariable svar; + + elog(DEBUG1, "pg_variable_cache_callback %u %u", cacheid, hashvalue); + + Assert(sessionvars); + + /* + * If the hashvalue is not specified, we have to recheck all currently + * used session variables. Since we can't tell the exact session variable + * from its hashvalue, we have to iterate over all items in the hash bucket. + */ + hash_seq_init(&status, sessionvars); + + while ((svar = (SVariable) hash_seq_search(&status)) != NULL) + { + if (hashvalue == 0 || svar->hashvalue == hashvalue) + { + svar->is_valid = false; + } + } +} + +/* + * Release stored value, free memory + */ +static void +free_session_variable_value(SVariable svar) +{ + /* clean the current value */ + if (!svar->isnull) + { + if (!svar->typbyval) + pfree(DatumGetPointer(svar->value)); + + svar->isnull = true; + } + + svar->value = (Datum) 0; +} + +/* + * Returns true when the entry in pg_variable is consistent with the given + * session variable. + */ +static bool +is_session_variable_valid(SVariable svar) +{ + HeapTuple tp; + bool result = false; + + Assert(OidIsValid(svar->varid)); + + tp = SearchSysCache1(VARIABLEOID, ObjectIdGetDatum(svar->varid)); + + if (HeapTupleIsValid(tp)) + { + /* + * The OID alone is not enough as an unique identifier, because OID + * values get recycled, and a new session variable could have got + * the same OID. We do a second check against the 64-bit LSN when + * the variable was created. + */ + if (svar->create_lsn == ((Form_pg_variable) GETSTRUCT(tp))->varcreate_lsn) + result = true; + + ReleaseSysCache(tp); + } + + return result; +} + +/* + * Initialize attributes cached in "svar" + */ +static void +setup_session_variable(SVariable svar, Oid varid) +{ + HeapTuple tup; + Form_pg_variable varform; + + Assert(OidIsValid(varid)); + + tup = SearchSysCache1(VARIABLEOID, ObjectIdGetDatum(varid)); + + if (!HeapTupleIsValid(tup)) + elog(ERROR, "cache lookup failed for session variable %u", varid); + + varform = (Form_pg_variable) GETSTRUCT(tup); + + svar->varid = varid; + svar->create_lsn = varform->varcreate_lsn; + + svar->typid = varform->vartype; + + get_typlenbyval(svar->typid, &svar->typlen, &svar->typbyval); + + svar->is_domain = (get_typtype(varform->vartype) == TYPTYPE_DOMAIN); + svar->domain_check_extra = NULL; + svar->domain_check_extra_lxid = InvalidLocalTransactionId; + + svar->isnull = true; + svar->value = (Datum) 0; + + svar->is_valid = true; + + svar->hashvalue = GetSysCacheHashValue1(VARIABLEOID, + ObjectIdGetDatum(varid)); + + ReleaseSysCache(tup); +} + +/* + * Assign a new value to the session variable. It is copied to + * SVariableMemoryContext if necessary. + * + * If any error happens, the existing value won't be modified. + */ +static void +set_session_variable(SVariable svar, Datum value, bool isnull) +{ + Datum newval; + SVariableData locsvar, + *_svar; + + Assert(svar); + Assert(!isnull || value == (Datum) 0); + + /* + * Use typbyval, typbylen from session variable only when they are + * trustworthy (the invalidation message was not accepted for this + * variable). If the variable might be invalid, force setup. + * + * Do not overwrite the passed session variable until we can be certain + * that no error can be thrown. + */ + if (!svar->is_valid) + { + setup_session_variable(&locsvar, svar->varid); + _svar = &locsvar; + } + else + _svar = svar; + + if (!isnull) + { + MemoryContext oldcxt = MemoryContextSwitchTo(SVariableMemoryContext); + + newval = datumCopy(value, _svar->typbyval, _svar->typlen); + + MemoryContextSwitchTo(oldcxt); + } + else + newval = value; + + free_session_variable_value(svar); + + elog(DEBUG1, "session variable \"%s.%s\" (oid:%u) has new value", + get_namespace_name(get_session_variable_namespace(svar->varid)), + get_session_variable_name(svar->varid), + svar->varid); + + /* no more error expected, so we can overwrite the old variable now */ + if (svar != _svar) + memcpy(svar, _svar, sizeof(SVariableData)); + + svar->value = newval; + svar->isnull = isnull; +} + +/* + * Create the hash table for storing session variables. + */ +static void +create_sessionvars_hashtables(void) +{ + HASHCTL vars_ctl; + + Assert(!sessionvars); + + if (!SVariableMemoryContext) + { + /* read sinval messages */ + CacheRegisterSyscacheCallback(VARIABLEOID, + pg_variable_cache_callback, + (Datum) 0); + + /* we need our own long-lived memory context */ + SVariableMemoryContext = + AllocSetContextCreate(TopMemoryContext, + "session variables", + ALLOCSET_START_SMALL_SIZES); + } + + memset(&vars_ctl, 0, sizeof(vars_ctl)); + vars_ctl.keysize = sizeof(Oid); + vars_ctl.entrysize = sizeof(SVariableData); + vars_ctl.hcxt = SVariableMemoryContext; + + sessionvars = hash_create("Session variables", 64, &vars_ctl, + HASH_ELEM | HASH_BLOBS | HASH_CONTEXT); +} + +/* + * Search a session variable in the hash table given its OID. If it + * doesn't exist, then insert it there. + * + * The caller is responsible for doing permission checks. + * + * As a side effect, this function acquires a AccessShareLock on the + * session variable until the end of the transaction. + */ +static SVariable +get_session_variable(Oid varid) +{ + SVariable svar; + bool found; + + /* protect the used session variable against DROP */ + LockDatabaseObject(VariableRelationId, varid, 0, AccessShareLock); + + if (!sessionvars) + create_sessionvars_hashtables(); + + svar = (SVariable) hash_search(sessionvars, &varid, + HASH_ENTER, &found); + + if (found) + { + if (!svar->is_valid) + { + /* + * If there was an invalidation message, the variable might still be + * valid, but we have to check with the system catalog. + */ + if (is_session_variable_valid(svar)) + svar->is_valid = true; + else + /* if the value cannot be validated, we have to discard it */ + free_session_variable_value(svar); + } + } + else + svar->is_valid = false; + + /* + * Force setup for not yet initialized variables or variables that cannot + * be validated. + */ + if (!svar->is_valid) + { + setup_session_variable(svar, varid); + + elog(DEBUG1, "session variable \"%s.%s\" (oid:%u) has assigned entry in memory (emitted by READ)", + get_namespace_name(get_session_variable_namespace(varid)), + get_session_variable_name(varid), + varid); + } + + /* ensure the returned data is still of the correct domain */ + if (svar->is_domain) + { + /* + * Store "extra" for domain_check() in TopTransactionContext. When we + * are in a new transaction, domain_check_extra cache is not valid any + * more. + */ + if (svar->domain_check_extra_lxid != MyProc->vxid.lxid) + svar->domain_check_extra = NULL; + + domain_check(svar->value, svar->isnull, + svar->typid, &svar->domain_check_extra, + TopTransactionContext); + + svar->domain_check_extra_lxid = MyProc->vxid.lxid; + } + + return svar; +} + +/* + * Store the given value in a session variable in the cache. + * + * The caller is responsible for doing permission checks. + * + * As a side effect, this function acquires a AccessShareLock on the session + * variable until the end of the transaction. + */ +void +SetSessionVariable(Oid varid, Datum value, bool isNull) +{ + SVariable svar; + bool found; + + /* protect used session variable against DROP */ + LockDatabaseObject(VariableRelationId, varid, 0, AccessShareLock); + + if (!sessionvars) + create_sessionvars_hashtables(); + + svar = (SVariable) hash_search(sessionvars, &varid, + HASH_ENTER, &found); + + if (!found) + { + setup_session_variable(svar, varid); + + elog(DEBUG1, "session variable \"%s.%s\" (oid:%u) has assigned entry in memory (emitted by WRITE)", + get_namespace_name(get_session_variable_namespace(svar->varid)), + get_session_variable_name(svar->varid), + varid); + } + + /* if this fails, it won't change the stored value */ + set_session_variable(svar, value, isNull); +} + +/* + * Wrapper around SetSessionVariable with permission checks. + */ +void +SetSessionVariableWithSecurityCheck(Oid varid, Datum value, bool isNull) +{ + AclResult aclresult; + + /* is the caller allowed to update the session variable? */ + aclresult = object_aclcheck(VariableRelationId, varid, GetUserId(), ACL_UPDATE); + if (aclresult != ACLCHECK_OK) + aclcheck_error(aclresult, OBJECT_VARIABLE, get_session_variable_name(varid)); + + SetSessionVariable(varid, value, isNull); +} + +/* + * Returns a copy of the value stored in a variable. + */ +static inline Datum +copy_session_variable_value(SVariable svar, bool *isNull) +{ + Datum value; + + /* force copy of non NULL value */ + if (!svar->isnull) + { + value = datumCopy(svar->value, svar->typbyval, svar->typlen); + *isNull = false; + } + else + { + value = (Datum) 0; + *isNull = true; + } + + return value; +} + +/* + * Returns a copy of the value of the session variable (in the current memory + * context). The caller is responsible for permission checks. + */ +Datum +GetSessionVariable(Oid varid, bool *isNull, Oid *typid) +{ + SVariable svar; + + svar = get_session_variable(varid); + + /* + * Although "svar" is freshly validated in this point, svar->is_valid can + * be false, if an invalidation message ws processed during the domain check. + * But the variable and all its dependencies are locked now, so we don't need + * to repeat the validation. + */ + Assert(svar); + + *typid = svar->typid; + + return copy_session_variable_value(svar, isNull); +} + +/* + * Returns a copy of the value of the session variable after checking if the + * type is the same as "expected_typid". The caller is responsible for + * permission checks. + */ +Datum +GetSessionVariableWithTypeCheck(Oid varid, bool *isNull, Oid expected_typid) +{ + SVariable svar; + + svar = get_session_variable(varid); + + Assert(svar && svar->is_valid); + + if (expected_typid != svar->typid) + elog(ERROR, "type of variable \"%s.%s\" is different than expected", + get_namespace_name(get_session_variable_namespace(varid)), + get_session_variable_name(varid)); + + return copy_session_variable_value(svar, isNull); +} + +/* + * Assign the result of the evaluated expression to the session variable + */ +void +ExecuteLetStmt(ParseState *pstate, + LetStmt *stmt, + ParamListInfo params, + QueryEnvironment *queryEnv, + QueryCompletion *qc) +{ + Query *query = castNode(Query, stmt->query); + List *rewritten; + DestReceiver *dest; + AclResult aclresult; + PlannedStmt *plan; + QueryDesc *queryDesc; + Oid varid = query->resultVariable; + + Assert(OidIsValid(varid)); + + /* do we have permission to write to the session variable? */ + aclresult = object_aclcheck(VariableRelationId, varid, GetUserId(), ACL_UPDATE); + if (aclresult != ACLCHECK_OK) + aclcheck_error(aclresult, OBJECT_VARIABLE, get_session_variable_name(varid)); + + /* create a dest receiver for LET */ + dest = CreateVariableDestReceiver(varid); + + /* run the query rewriter */ + query = copyObject(query); + + rewritten = QueryRewrite(query); + + Assert(list_length(rewritten) == 1); + + query = linitial_node(Query, rewritten); + Assert(query->commandType == CMD_SELECT); + + /* plan the query */ + plan = pg_plan_query(query, pstate->p_sourcetext, + CURSOR_OPT_PARALLEL_OK, params); + + /* + * Use a snapshot with an updated command ID to ensure this query sees the + * results of any previously executed queries. (This could only matter if + * the planner executed an allegedly-stable function that changed the + * database contents, but let's do it anyway to be parallel to the EXPLAIN + * code path.) + */ + PushCopiedSnapshot(GetActiveSnapshot()); + UpdateActiveSnapshotCommandId(); + + /* create a QueryDesc, redirecting output to our tuple receiver */ + queryDesc = CreateQueryDesc(plan, pstate->p_sourcetext, + GetActiveSnapshot(), InvalidSnapshot, + dest, params, queryEnv, 0); + + /* call ExecutorStart to prepare the plan for execution */ + ExecutorStart(queryDesc, 0); + + /* + * Run the plan to completion. The result should be only one row. To + * check if there are too many result rows, we try to fetch two. + */ + ExecutorRun(queryDesc, ForwardScanDirection, 2L, true); + + /* save the rowcount if we're given a QueryCompletion to fill */ + if (qc) + SetQueryCompletion(qc, CMDTAG_LET, queryDesc->estate->es_processed); + + /* and clean up */ + ExecutorFinish(queryDesc); + ExecutorEnd(queryDesc); + + FreeQueryDesc(queryDesc); + + PopActiveSnapshot(); +} diff --git a/src/backend/executor/Makefile b/src/backend/executor/Makefile index 11118d0ce02..71248a34f26 100644 --- a/src/backend/executor/Makefile +++ b/src/backend/executor/Makefile @@ -76,6 +76,7 @@ OBJS = \ nodeWindowAgg.o \ nodeWorktablescan.o \ spi.o \ + svariableReceiver.o \ tqueue.o \ tstoreReceiver.o diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c index c8077aa57bd..b1a5a167b10 100644 --- a/src/backend/executor/execExpr.c +++ b/src/backend/executor/execExpr.c @@ -34,6 +34,7 @@ #include "catalog/objectaccess.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" +#include "catalog/pg_variable.h" #include "executor/execExpr.h" #include "executor/nodeSubplan.h" #include "funcapi.h" @@ -991,6 +992,41 @@ ExecInitExprRec(Expr *node, ExprState *state, scratch.d.param.paramtype = param->paramtype; ExprEvalPushStep(state, &scratch); break; + + case PARAM_VARIABLE: + { + int es_num_session_variables = 0; + SessionVariableValue *es_session_variables = NULL; + SessionVariableValue *var; + + if (state->parent && state->parent->state) + { + es_session_variables = state->parent->state->es_session_variables; + es_num_session_variables = state->parent->state->es_num_session_variables; + } + + Assert(es_session_variables); + + /* parameter sanity checks */ + if (param->paramid >= es_num_session_variables) + elog(ERROR, "paramid of PARAM_VARIABLE param is out of range"); + + var = &es_session_variables[param->paramid]; + + if (var->typid != param->paramtype) + elog(ERROR, "type of buffered value is different than PARAM_VARIABLE type"); + + /* + * In this case, pass the value like a + * constant. + */ + scratch.opcode = EEOP_CONST; + scratch.d.constval.value = var->value; + scratch.d.constval.isnull = var->isnull; + ExprEvalPushStep(state, &scratch); + } + break; + case PARAM_EXTERN: /* diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 29e186fa73d..67fad7eeb83 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -43,7 +43,9 @@ #include "access/xact.h" #include "catalog/namespace.h" #include "catalog/partition.h" +#include "catalog/pg_variable.h" #include "commands/matview.h" +#include "commands/session_variable.h" #include "commands/trigger.h" #include "executor/executor.h" #include "executor/nodeSubplan.h" @@ -191,6 +193,61 @@ standard_ExecutorStart(QueryDesc *queryDesc, int eflags) Assert(queryDesc->sourceText != NULL); estate->es_sourceText = queryDesc->sourceText; + /* + * The executor doesn't work with session variables directly. Values of + * related session variables are copied to a dedicated array, and this array + * is passed to the executor. This array is stable "snapshot" of values of + * used session variables. There are three benefits of this strategy: + * + * - consistency with external parameters and plpgsql variables, + * + * - session variables can be parallel safe, + * + * - we don't need make fresh copy for any read of session variable + * (this is necessary because the internally the session variable can + * be changed inside query execution time, and then a reference to + * previously returned value can be corrupted). + */ + if (queryDesc->plannedstmt->sessionVariables) + { + ListCell *lc; + int nSessionVariables; + int i = 0; + + /* + * In this case, the query uses session variables, but we have to + * prepare the array with passed values (of used session variables) + * first. + */ + Assert(!IsParallelWorker()); + nSessionVariables = list_length(queryDesc->plannedstmt->sessionVariables); + + /* create the array used for passing values of used session variables */ + estate->es_session_variables = (SessionVariableValue *) + palloc(nSessionVariables * sizeof(SessionVariableValue)); + + /* fill the array */ + foreach(lc, queryDesc->plannedstmt->sessionVariables) + { + AclResult aclresult; + Oid varid = lfirst_oid(lc); + + aclresult = object_aclcheck(VariableRelationId, varid, GetUserId(), ACL_SELECT); + if (aclresult != ACLCHECK_OK) + aclcheck_error(aclresult, OBJECT_VARIABLE, + get_session_variable_name(varid)); + + estate->es_session_variables[i].varid = varid; + estate->es_session_variables[i].value = GetSessionVariable(varid, + &estate->es_session_variables[i].isnull, + &estate->es_session_variables[i].typid); + + i++; + } + + estate->es_num_session_variables = nSessionVariables; + } + /* * Fill in the query environment, if any, from queryDesc. */ diff --git a/src/backend/executor/meson.build b/src/backend/executor/meson.build index b511a429adf..b6662c6e8fc 100644 --- a/src/backend/executor/meson.build +++ b/src/backend/executor/meson.build @@ -64,6 +64,7 @@ backend_sources += files( 'nodeWindowAgg.c', 'nodeWorktablescan.c', 'spi.c', + 'svariableReceiver.c', 'tqueue.c', 'tstoreReceiver.c', ) diff --git a/src/backend/executor/svariableReceiver.c b/src/backend/executor/svariableReceiver.c new file mode 100644 index 00000000000..c4cff44ecf4 --- /dev/null +++ b/src/backend/executor/svariableReceiver.c @@ -0,0 +1,201 @@ +/*------------------------------------------------------------------------- + * + * svariableReceiver.c + * An implementation of DestReceiver that stores the result value in + * a session variable. + * + * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/executor/svariableReceiver.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" +#include "miscadmin.h" + +#include "access/detoast.h" +#include "catalog/pg_variable.h" +#include "commands/session_variable.h" +#include "executor/svariableReceiver.h" +#include "storage/lock.h" +#include "utils/builtins.h" +#include "utils/lsyscache.h" +#include "utils/syscache.h" + +/* + * This DestReceiver is used by the LET command for storing the result to a + * session variable. The result has to have only one tuple with only one + * non-deleted attribute. The row counter (field "rows") is incremented + * after receiving a row, and an error is raised when there are no rows or + * there are more than one received rows. Because a received tuple can have + * deleted attributes, we need to find the first non-deleted attribute + * (field "slot_offset"). The value is detoasted before storing it in the + * session variable. + */ +typedef struct +{ + DestReceiver pub; + Oid varid; + bool need_detoast; /* do we need to detoast the attribute? */ + int slot_offset; /* position of non-deleted attribute */ + int rows; /* row counter */ +} SVariableState; + +/* + * Prepare to receive tuples from executor. + */ +static void +svariableStartupReceiver(DestReceiver *self, int operation, TupleDesc typeinfo) +{ + SVariableState *myState = (SVariableState *) self; + int natts = typeinfo->natts; + int outcols = 0; + int i; + LOCKTAG locktag PG_USED_FOR_ASSERTS_ONLY; + + Assert(myState->pub.mydest == DestVariable); + Assert(OidIsValid(myState->varid)); + Assert(SearchSysCacheExists1(VARIABLEOID, myState->varid)); + +#ifdef USE_ASSERT_CHECKING + + SET_LOCKTAG_OBJECT(locktag, + MyDatabaseId, + VariableRelationId, + myState->varid, + 0); + + Assert(LockHeldByMe(&locktag, AccessShareLock, false)); + +#endif + + for (i = 0; i < natts; i++) + { + Form_pg_attribute attr = TupleDescAttr(typeinfo, i); + Oid typid; + Oid collid; + int32 typmod; + + if (attr->attisdropped) + continue; + + if (++outcols > 1) + continue; + + get_session_variable_type_typmod_collid(myState->varid, + &typid, + &typmod, + &collid); + + /* + * Double check - the type and typmod of target variable should be the + * same as the type and typmod of assignment expression. The + * expression should be wrapped by a cast to the target type/typmod. + */ + if (attr->atttypid != typid || + (attr->atttypmod >= 0 && + attr->atttypmod != typmod)) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("target session variable is of type %s" + " but expression is of type %s", + format_type_with_typemod(typid, typmod), + format_type_with_typemod(attr->atttypid, + attr->atttypmod)))); + + myState->need_detoast = attr->attlen == -1; + myState->slot_offset = i; + } + + if (outcols != 1) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg_plural("assignment expression returned %d column", + "assignment expression returned %d columns", + outcols, + outcols))); + + myState->rows = 0; +} + +/* + * Receive a tuple from the executor and store it in the session variable. + */ +static bool +svariableReceiveSlot(TupleTableSlot *slot, DestReceiver *self) +{ + SVariableState *myState = (SVariableState *) self; + Datum value; + bool isnull; + bool freeval = false; + + /* make sure the tuple is fully deconstructed */ + slot_getallattrs(slot); + + value = slot->tts_values[myState->slot_offset]; + isnull = slot->tts_isnull[myState->slot_offset]; + + if (myState->need_detoast && !isnull && VARATT_IS_EXTERNAL(DatumGetPointer(value))) + { + value = PointerGetDatum(detoast_external_attr((struct varlena *) + DatumGetPointer(value))); + freeval = true; + } + + myState->rows += 1; + + if (myState->rows > 1) + ereport(ERROR, + (errcode(ERRCODE_TOO_MANY_ROWS), + errmsg("expression returned more than one row"))); + + SetSessionVariable(myState->varid, value, isnull); + + if (freeval) + pfree(DatumGetPointer(value)); + + return true; +} + +/* + * Clean up at end of the executor run + */ +static void +svariableShutdownReceiver(DestReceiver *self) +{ + if (((SVariableState *) self)->rows == 0) + ereport(ERROR, + (errcode(ERRCODE_NO_DATA_FOUND), + errmsg("expression returned no rows"))); +} + +/* + * Destroy the receiver when we are done with it + */ +static void +svariableDestroyReceiver(DestReceiver *self) +{ + pfree(self); +} + +/* + * Initially create a DestReceiver object. + */ +DestReceiver * +CreateVariableDestReceiver(Oid varid) +{ + SVariableState *self = (SVariableState *) palloc0(sizeof(SVariableState)); + + self->pub.receiveSlot = svariableReceiveSlot; + self->pub.rStartup = svariableStartupReceiver; + self->pub.rShutdown = svariableShutdownReceiver; + self->pub.rDestroy = svariableDestroyReceiver; + self->pub.mydest = DestVariable; + + self->varid = varid; + + return (DestReceiver *) self; +} diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c index 0d00e029f32..210d911963b 100644 --- a/src/backend/nodes/nodeFuncs.c +++ b/src/backend/nodes/nodeFuncs.c @@ -4342,6 +4342,16 @@ raw_expression_tree_walker_impl(Node *node, return true; } break; + case T_LetStmt: + { + LetStmt *stmt = (LetStmt *) node; + + if (WALK(stmt->target)) + return true; + if (WALK(stmt->query)) + return true; + } + break; case T_PLAssignStmt: { PLAssignStmt *stmt = (PLAssignStmt *) node; diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index df35d1ff9c4..1d10509c93f 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -325,6 +325,7 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, glob->lastPlanNodeId = 0; glob->transientPlan = false; glob->dependsOnRole = false; + glob->sessionVariables = NIL; /* * Assess whether it's feasible to use parallel mode for this query. We @@ -559,6 +560,7 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, result->paramExecTypes = glob->paramExecTypes; /* utilityStmt should be null, but we might as well copy it */ result->utilityStmt = parse->utilityStmt; + result->sessionVariables = glob->sessionVariables; result->stmt_location = parse->stmt_location; result->stmt_len = parse->stmt_len; @@ -729,6 +731,13 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root, */ pull_up_subqueries(root); + /* + * Check if some subquery uses a session variable. The flag + * hasSessionVariables should be true if the query or some subquery uses a + * session variable. + */ + pull_up_has_session_variables(root); + /* * If this is a simple UNION ALL query, flatten it into an appendrel. We * do this now because it requires applying pull_up_subqueries to the leaf diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c index 91c7c4fe2fe..1fa2ecf5c20 100644 --- a/src/backend/optimizer/plan/setrefs.c +++ b/src/backend/optimizer/plan/setrefs.c @@ -210,6 +210,9 @@ static List *set_returning_clause_references(PlannerInfo *root, static List *set_windowagg_runcondition_references(PlannerInfo *root, List *runcondition, Plan *plan); +static bool pull_up_has_session_variables_walker(Node *node, + PlannerInfo *root); +static void record_plan_variable_dependency(PlannerInfo *root, Oid varid); /***************************************************************************** @@ -1310,6 +1313,50 @@ set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset) return plan; } +/* + * Search usage of session variables in subqueries + */ +void +pull_up_has_session_variables(PlannerInfo *root) +{ + Query *query = root->parse; + + if (query->hasSessionVariables) + { + root->hasSessionVariables = true; + } + else + { + (void) query_tree_walker(query, + pull_up_has_session_variables_walker, + (void *) root, 0); + } +} + +static bool +pull_up_has_session_variables_walker(Node *node, PlannerInfo *root) +{ + if (node == NULL) + return false; + if (IsA(node, Query)) + { + Query *query = (Query *) node; + + if (query->hasSessionVariables) + { + root->hasSessionVariables = true; + return false; + } + + /* recurse into subselects */ + return query_tree_walker((Query *) node, + pull_up_has_session_variables_walker, + (void *) root, 0); + } + return expression_tree_walker(node, pull_up_has_session_variables_walker, + (void *) root); +} + /* * set_indexonlyscan_references * Do set_plan_references processing on an IndexOnlyScan @@ -1958,8 +2005,9 @@ copyVar(Var *var) * This is code that is common to all variants of expression-fixing. * We must look up operator opcode info for OpExpr and related nodes, * add OIDs from regclass Const nodes into root->glob->relationOids, and - * add PlanInvalItems for user-defined functions into root->glob->invalItems. - * We also fill in column index lists for GROUPING() expressions. + * add PlanInvalItems for user-defined functions and session variables into + * root->glob->invalItems. We also fill in column index lists for GROUPING() + * expressions. * * We assume it's okay to update opcode info in-place. So this could possibly * scribble on the planner's input data structures, but it's OK. @@ -2049,6 +2097,13 @@ fix_expr_common(PlannerInfo *root, Node *node) g->cols = cols; } } + else if (IsA(node, Param)) + { + Param *p = (Param *) node; + + if (p->paramkind == PARAM_VARIABLE) + record_plan_variable_dependency(root, p->paramvarid); + } } /* @@ -2058,6 +2113,10 @@ fix_expr_common(PlannerInfo *root, Node *node) * If it's a PARAM_MULTIEXPR, replace it with the appropriate Param from * root->multiexpr_params; otherwise no change is needed. * Just for paranoia's sake, we make a copy of the node in either case. + * + * If it's a PARAM_VARIABLE, then we collect used session variables in + * the list root->glob->sessionVariable. Also, assign the parameter's + * "paramid" to the parameter's position in that list. */ static Node * fix_param_node(PlannerInfo *root, Param *p) @@ -2076,6 +2135,41 @@ fix_param_node(PlannerInfo *root, Param *p) elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid); return copyObject(list_nth(params, colno - 1)); } + + if (p->paramkind == PARAM_VARIABLE) + { + ListCell *lc; + int n = 0; + bool found = false; + + /* we will modify object */ + p = (Param *) copyObject(p); + + /* + * Now, we can actualize list of session variables, and we can + * complete paramid parameter. + */ + foreach(lc, root->glob->sessionVariables) + { + if (lfirst_oid(lc) == p->paramvarid) + { + p->paramid = n; + found = true; + break; + } + n += 1; + } + + if (!found) + { + root->glob->sessionVariables = lappend_oid(root->glob->sessionVariables, + p->paramvarid); + p->paramid = n; + } + + return (Node *) p; + } + return (Node *) copyObject(p); } @@ -2137,7 +2231,10 @@ fix_alternative_subplan(PlannerInfo *root, AlternativeSubPlan *asplan, * replacing Aggref nodes that should be replaced by initplan output Params, * choosing the best implementation for AlternativeSubPlans, * looking up operator opcode info for OpExpr and related nodes, - * and adding OIDs from regclass Const nodes into root->glob->relationOids. + * adding OIDs from regclass Const nodes into root->glob->relationOids, + * assigning paramvarid to PARAM_VARIABLE params, and collecting the + * OIDs of session variables in the root->glob->sessionVariables list + * (paramvarid is the position of the session variable in this list). * * 'node': the expression to be modified * 'rtoffset': how much to increment varnos by @@ -2159,7 +2256,8 @@ fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset, double num_exec) root->multiexpr_params != NIL || root->glob->lastPHId != 0 || root->minmax_aggs != NIL || - root->hasAlternativeSubPlans) + root->hasAlternativeSubPlans || + root->hasSessionVariables) { return fix_scan_expr_mutator(node, &context); } @@ -3544,6 +3642,25 @@ record_plan_type_dependency(PlannerInfo *root, Oid typid) } } +/* + * Record dependency on a session variable. The variable can be used as a + * session variable in an expression list, or as the target of a LET statement. + */ +static void +record_plan_variable_dependency(PlannerInfo *root, Oid varid) +{ + PlanInvalItem *inval_item = makeNode(PlanInvalItem); + + /* paramid is still session variable id */ + inval_item->cacheId = VARIABLEOID; + inval_item->hashValue = GetSysCacheHashValue1(VARIABLEOID, + ObjectIdGetDatum(varid)); + + /* append this variable to global, register dependency */ + root->glob->invalItems = lappend(root->glob->invalItems, + inval_item); +} + /* * extract_query_dependencies * Given a rewritten, but not yet planned, query or queries @@ -3629,9 +3746,9 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context) } /* - * Ignore other utility statements, except those (such as EXPLAIN) - * that contain a parsed-but-not-planned query. For those, we - * just need to transfer our attention to the contained query. + * Ignore other utility statements, except those (such as EXPLAIN + * or LET) that contain a parsed-but-not-planned query. For those, + * we just need to transfer our attention to the contained query. */ query = UtilityContainsQuery(query->utilityStmt); if (query == NULL) @@ -3654,6 +3771,10 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context) lappend_oid(context->glob->relationOids, rte->relid); } + /* record dependency on the target variable of a LET command */ + if (OidIsValid(query->resultVariable)) + record_plan_variable_dependency(context, query->resultVariable); + /* And recurse into the query's subexpressions */ return query_tree_walker(query, extract_query_dependencies_walker, (void *) context, 0); diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c index a70404558ff..aa3ce219cd7 100644 --- a/src/backend/optimizer/prep/prepjointree.c +++ b/src/backend/optimizer/prep/prepjointree.c @@ -1315,6 +1315,9 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte, /* If subquery had any RLS conditions, now main query does too */ parse->hasRowSecurity |= subquery->hasRowSecurity; + /* if the subquery had session variables, the main query does too */ + parse->hasSessionVariables |= subquery->hasSessionVariables; + /* * subquery won't be pulled up if it hasAggs, hasWindowFuncs, or * hasTargetSRFs, so no work needed on those flags diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index b4e085e9d4b..0063b2b6322 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -24,6 +24,7 @@ #include "catalog/pg_operator.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" +#include "commands/session_variable.h" #include "executor/executor.h" #include "executor/functions.h" #include "funcapi.h" @@ -935,6 +936,13 @@ max_parallel_hazard_walker(Node *node, max_parallel_hazard_context *context) if (param->paramkind == PARAM_EXTERN) return false; + /* we don't support passing session variables to workers */ + if (param->paramkind == PARAM_VARIABLE) + { + if (max_parallel_hazard_test(PROPARALLEL_RESTRICTED, context)) + return true; + } + if (param->paramkind != PARAM_EXEC || !list_member_int(context->safe_param_ids, param->paramid)) { @@ -2389,6 +2397,7 @@ convert_saop_to_hashed_saop_walker(Node *node, void *context) * value of the Param. * 2. Fold stable, as well as immutable, functions to constants. * 3. Reduce PlaceHolderVar nodes to their contained expressions. + * 4. Current value of session variable can be used for estimation too. *-------------------- */ Node * @@ -2515,6 +2524,29 @@ eval_const_expressions_mutator(Node *node, } } } + else if (param->paramkind == PARAM_VARIABLE && + context->estimate) + { + int16 typLen; + bool typByVal; + Datum pval; + bool isnull; + + get_typlenbyval(param->paramtype, + &typLen, &typByVal); + + pval = GetSessionVariableWithTypeCheck(param->paramvarid, + &isnull, + param->paramtype); + + return (Node *) makeConst(param->paramtype, + param->paramtypmod, + param->paramcollid, + (int) typLen, + pval, + isnull, + typByVal); + } /* * Not replaceable, so just copy the Param (no need to @@ -4706,7 +4738,8 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid, querytree->limitOffset || querytree->limitCount || querytree->setOperations || - list_length(querytree->targetList) != 1) + (list_length(querytree->targetList) != 1) || + querytree->hasSessionVariables) goto fail; /* If the function result is composite, resolve it */ diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index e901203424d..f53653aa368 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -25,9 +25,12 @@ #include "postgres.h" #include "access/sysattr.h" +#include "catalog/namespace.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" +#include "catalog/pg_variable.h" #include "commands/defrem.h" +#include "commands/session_variable.h" #include "miscadmin.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" @@ -51,6 +54,7 @@ #include "utils/backend_status.h" #include "utils/builtins.h" #include "utils/guc.h" +#include "utils/lsyscache.h" #include "utils/rel.h" #include "utils/syscache.h" @@ -83,6 +87,8 @@ static Query *transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt); static Query *transformCallStmt(ParseState *pstate, CallStmt *stmt); +static Query *transformLetStmt(ParseState *pstate, + LetStmt *stmt); static void transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc, bool pushedDown); #ifdef DEBUG_NODE_TESTS_ENABLED @@ -330,6 +336,7 @@ transformStmt(ParseState *pstate, Node *parseTree) case T_UpdateStmt: case T_DeleteStmt: case T_MergeStmt: + case T_LetStmt: (void) test_raw_expression_coverage(parseTree, NULL); break; default: @@ -409,6 +416,11 @@ transformStmt(ParseState *pstate, Node *parseTree) (CallStmt *) parseTree); break; + case T_LetStmt: + result = transformLetStmt(pstate, + (LetStmt *) parseTree); + break; + default: /* @@ -460,6 +472,7 @@ stmt_requires_parse_analysis(RawStmt *parseTree) case T_SelectStmt: case T_ReturnStmt: case T_PLAssignStmt: + case T_LetStmt: result = true; break; @@ -568,6 +581,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt) qry->hasWindowFuncs = pstate->p_hasWindowFuncs; qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasAggs = pstate->p_hasAggs; + qry->hasSessionVariables = pstate->p_hasSessionVariables; assign_query_collations(pstate, qry); @@ -994,6 +1008,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt) qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasSubLinks = pstate->p_hasSubLinks; + qry->hasSessionVariables = pstate->p_hasSessionVariables; assign_query_collations(pstate, qry); @@ -1459,6 +1474,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt) qry->hasWindowFuncs = pstate->p_hasWindowFuncs; qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasAggs = pstate->p_hasAggs; + qry->hasSessionVariables = pstate->p_hasSessionVariables; foreach(l, stmt->lockingClause) { @@ -1685,12 +1701,235 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt) qry->jointree = makeFromExpr(pstate->p_joinlist, NULL); qry->hasSubLinks = pstate->p_hasSubLinks; + qry->hasSessionVariables = pstate->p_hasSessionVariables; assign_query_collations(pstate, qry); return qry; } +/* + * transformLetStmt - + * transform an Let Statement + */ +static Query * +transformLetStmt(ParseState *pstate, LetStmt *stmt) +{ + Query *query; + Query *result; + List *exprList = NIL; + List *exprListCoer = NIL; + ListCell *lc; + ListCell *indirection_head = NULL; + Query *selectQuery; + Oid varid; + char *attrname = NULL; + bool not_unique; + bool is_rowtype; + Oid typid; + int32 typmod; + Oid collid; + AclResult aclresult; + List *names = NULL; + int indirection_start; + int i = 0; + + /* there can't be any outer WITH to worry about */ + Assert(pstate->p_ctenamespace == NIL); + + names = NamesFromList(stmt->target); + + /* locks the variable with an AccessShareLock */ + varid = IdentifyVariable(names, &attrname, ¬_unique, false); + if (not_unique) + ereport(ERROR, + (errcode(ERRCODE_AMBIGUOUS_PARAMETER), + errmsg("target \"%s\" of LET command is ambiguous", + NameListToString(names)), + parser_errposition(pstate, stmt->location))); + + if (!OidIsValid(varid)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("session variable \"%s\" doesn't exist", + NameListToString(names)), + parser_errposition(pstate, stmt->location))); + + /* + * Calculate start of possible position of an indirection in list, and + * when it is inside the list, store pointer on first node of indirection. + */ + indirection_start = list_length(names) - (attrname ? 1 : 0); + if (list_length(stmt->target) > indirection_start) + indirection_head = list_nth_cell(stmt->target, indirection_start); + + get_session_variable_type_typmod_collid(varid, &typid, &typmod, &collid); + + is_rowtype = type_is_rowtype(typid); + + if (attrname && !is_rowtype) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("type \"%s\" of target session variable \"%s.%s\" is not a composite type", + format_type_be(typid), + get_namespace_name(get_session_variable_namespace(varid)), + get_session_variable_name(varid)), + parser_errposition(pstate, stmt->location))); + + aclresult = object_aclcheck(VariableRelationId, varid, GetUserId(), ACL_UPDATE); + if (aclresult != ACLCHECK_OK) + aclcheck_error(aclresult, OBJECT_VARIABLE, NameListToString(names)); + + pstate->p_expr_kind = EXPR_KIND_LET_TARGET; + + /* we need to postpone conversion of "unknown" to text */ + pstate->p_resolve_unknowns = false; + + selectQuery = transformStmt(pstate, stmt->query); + + /* the grammar should have produced a SELECT */ + Assert(IsA(selectQuery, Query) && selectQuery->commandType == CMD_SELECT); + + /* + * Generate an expression list for the LET that selects all the non-resjunk + * columns from the subquery. + */ + exprList = NIL; + foreach(lc, selectQuery->targetList) + { + TargetEntry *tle = (TargetEntry *) lfirst(lc); + + if (tle->resjunk) + continue; + + exprList = lappend(exprList, tle->expr); + } + + /* don't allow multicolumn result */ + if (list_length(exprList) != 1) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg_plural("assignment expression returned %d column", + "assignment expression returned %d columns", + list_length(exprList), + list_length(exprList)), + parser_errposition(pstate, + exprLocation((Node *) exprList)))); + + exprListCoer = NIL; + + foreach(lc, exprList) + { + Expr *expr = (Expr *) lfirst(lc); + Expr *coerced_expr; + Param *param; + Oid exprtypid; + + /* now we can read the type of the expression */ + exprtypid = exprType((Node *) expr); + + param = makeNode(Param); + param->paramkind = PARAM_VARIABLE; + param->paramvarid = varid; + param->paramtype = typid; + param->paramtypmod = typmod; + + if (indirection_head) + { + bool targetIsArray; + char *targetName; + + targetName = get_session_variable_name(varid); + targetIsArray = OidIsValid(get_element_type(typid)); + + pstate->p_hasSessionVariables = true; + + coerced_expr = (Expr *) + transformAssignmentIndirection(pstate, + (Node *) param, + targetName, + targetIsArray, + typid, + typmod, + InvalidOid, + stmt->target, + indirection_head, + (Node *) expr, + COERCION_ASSIGNMENT, + stmt->location); + } + else + coerced_expr = (Expr *) + coerce_to_target_type(pstate, + (Node *) expr, + exprtypid, + typid, typmod, + COERCION_ASSIGNMENT, + COERCE_IMPLICIT_CAST, + stmt->location); + + if (coerced_expr == NULL) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("variable \"%s.%s\" is of type %s," + " but expression is of type %s", + get_namespace_name(get_session_variable_namespace(varid)), + get_session_variable_name(varid), + format_type_be(typid), + format_type_be(exprtypid)), + errhint("You will need to rewrite or cast the expression."), + parser_errposition(pstate, exprLocation((Node *) expr)))); + + exprListCoer = lappend(exprListCoer, coerced_expr); + } + + /* generate query's target list using the computed list of expressions */ + query = makeNode(Query); + query->commandType = CMD_SELECT; + + foreach(lc, exprListCoer) + { + Expr *expr = (Expr *) lfirst(lc); + TargetEntry *tle; + + tle = makeTargetEntry(expr, + i + 1, + FigureColname((Node *) expr), + false); + query->targetList = lappend(query->targetList, tle); + } + + /* done building the range table and jointree */ + query->rtable = pstate->p_rtable; + query->jointree = makeFromExpr(pstate->p_joinlist, NULL); + + query->hasTargetSRFs = pstate->p_hasTargetSRFs; + query->hasSubLinks = pstate->p_hasSubLinks; + query->hasSessionVariables = pstate->p_hasSessionVariables; + + /* this is top-level query */ + query->canSetTag = true; + + /* + * Save target session variable ID. This value is used multiple times: by + * the query rewriter (for getting related defexpr), by planner (for + * acquiring an AccessShareLock on target variable), and by the executor + * (we need to know the target variable ID). + */ + query->resultVariable = varid; + + assign_query_collations(pstate, query); + + stmt->query = (Node *) query; + + /* represent the command as a utility Query */ + result = makeNode(Query); + result->commandType = CMD_UTILITY; + result->utilityStmt = (Node *) stmt; + + return result; +} + /* * transformSetOperationStmt - * transforms a set-operations tree @@ -1936,6 +2175,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt) qry->hasWindowFuncs = pstate->p_hasWindowFuncs; qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasAggs = pstate->p_hasAggs; + qry->hasSessionVariables = pstate->p_hasSessionVariables; foreach(l, lockingClause) { @@ -2410,6 +2650,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt) qry->hasWindowFuncs = pstate->p_hasWindowFuncs; qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasAggs = pstate->p_hasAggs; + qry->hasSessionVariables = pstate->p_hasSessionVariables; assign_query_collations(pstate, qry); @@ -2477,6 +2718,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt) qry->hasTargetSRFs = pstate->p_hasTargetSRFs; qry->hasSubLinks = pstate->p_hasSubLinks; + qry->hasSessionVariables = pstate->p_hasSessionVariables; assign_query_collations(pstate, qry); @@ -2664,9 +2906,15 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt) /* * Transform the target reference. Typically we will get back a Param * node, but there's no reason to be too picky about its type. + * + * Session variables should not be used as target of a PL/pgSQL assign + * statement. So we should use a dedicated expression kind and disallow + * session variables there. The dedicated context allows to eliminate + * undesirable warnings about the possibility of a target PL/pgSQL variable + * shadowing a session variable. */ target = transformExpr(pstate, (Node *) cref, - EXPR_KIND_UPDATE_TARGET); + EXPR_KIND_ASSIGN_TARGET); targettype = exprType(target); targettypmod = exprTypmod(target); targetcollation = exprCollation(target); @@ -2708,6 +2956,10 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt) */ type_id = exprType((Node *) tle->expr); + /* + * For indirection processing and additional casts we can use expr_kind + * EXPR_KIND_UPDATE_TARGET. + */ pstate->p_expr_kind = EXPR_KIND_UPDATE_TARGET; if (indirection) @@ -2850,6 +3102,8 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt) (LockingClause *) lfirst(l), false); } + qry->hasSessionVariables = pstate->p_hasSessionVariables; + assign_query_collations(pstate, qry); /* this must be done after collations, for reliable comparison of exprs */ @@ -3123,6 +3377,14 @@ transformCallStmt(ParseState *pstate, CallStmt *stmt) true, stmt->funccall->location); + /* + * The arguments of CALL statement are evaluated by a direct expression + * executor call. This path is unsupported yet, so block it. It will be + * enabled later. + */ + if (pstate->p_hasSessionVariables) + elog(ERROR, "session variable cannot be used as an argument"); + assign_expr_collations(pstate, node); fexpr = castNode(FuncExpr, node); diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 51b926ebdc0..be1e70e3ebf 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -306,7 +306,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); DropTransformStmt DropUserMappingStmt ExplainStmt FetchStmt GrantStmt GrantRoleStmt ImportForeignSchemaStmt IndexStmt InsertStmt - ListenStmt LoadStmt LockStmt MergeStmt NotifyStmt ExplainableStmt PreparableStmt + LetStmt ListenStmt LoadStmt LockStmt MergeStmt NotifyStmt ExplainableStmt PreparableStmt CreateFunctionStmt AlterFunctionStmt ReindexStmt RemoveAggrStmt RemoveFuncStmt RemoveOperStmt RenameStmt ReturnStmt RevokeStmt RevokeRoleStmt RuleActionStmt RuleActionStmtOrEmpty RuleStmt @@ -456,6 +456,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); TriggerTransitions TriggerReferencing vacuum_relation_list opt_vacuum_relation_list drop_option_list pub_obj_list + let_target %type opt_routine_body %type group_clause @@ -746,7 +747,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); KEEP KEY KEYS LABEL LANGUAGE LARGE_P LAST_P LATERAL_P - LEADING LEAKPROOF LEAST LEFT LEVEL LIKE LIMIT LISTEN LOAD LOCAL + LEADING LEAKPROOF LEAST LEFT LET LEVEL LIKE LIMIT LISTEN LOAD LOCAL LOCALTIME LOCALTIMESTAMP LOCATION LOCK_P LOCKED LOGGED MAPPING MATCH MATCHED MATERIALIZED MAXVALUE MERGE MERGE_ACTION METHOD @@ -1097,6 +1098,7 @@ stmt: | ImportForeignSchemaStmt | IndexStmt | InsertStmt + | LetStmt | ListenStmt | RefreshMatViewStmt | LoadStmt @@ -12698,6 +12700,47 @@ opt_hold: /* EMPTY */ { $$ = 0; } | WITHOUT HOLD { $$ = 0; } ; +/***************************************************************************** + * + * QUERY: + * LET STATEMENT + * + *****************************************************************************/ +LetStmt: LET let_target '=' a_expr + { + LetStmt *n = makeNode(LetStmt); + SelectStmt *select; + ResTarget *res; + + n->target = $2; + + select = makeNode(SelectStmt); + res = makeNode(ResTarget); + + /* create target list for implicit query */ + res->name = NULL; + res->indirection = NIL; + res->val = (Node *) $4; + res->location = @4; + + select->targetList = list_make1(res); + n->query = (Node *) select; + + n->location = @2; + $$ = (Node *) n; + } + ; + +let_target: + ColId opt_indirection + { + $$ = list_make1(makeString($1)); + if ($2) + $$ = list_concat($$, + check_indirection($2, yyscanner)); + } + ; + /***************************************************************************** * * QUERY: @@ -17729,6 +17772,7 @@ unreserved_keyword: | LARGE_P | LAST_P | LEAKPROOF + | LET | LEVEL | LISTEN | LOAD @@ -18339,6 +18383,7 @@ bare_label_keyword: | LEAKPROOF | LEAST | LEFT + | LET | LEVEL | LIKE | LISTEN diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c index efa730c1676..a7343001f21 100644 --- a/src/backend/parser/parse_agg.c +++ b/src/backend/parser/parse_agg.c @@ -580,6 +580,11 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr) errkind = true; break; + case EXPR_KIND_ASSIGN_TARGET: + case EXPR_KIND_LET_TARGET: + errkind = true; + break; + /* * There is intentionally no default: case here, so that the * compiler will warn if we add a new ParseExprKind without @@ -970,6 +975,10 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc, case EXPR_KIND_CYCLE_MARK: errkind = true; break; + case EXPR_KIND_ASSIGN_TARGET: + case EXPR_KIND_LET_TARGET: + errkind = true; + break; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 36c1b7a88f2..8760876c686 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -18,6 +18,7 @@ #include "catalog/pg_aggregate.h" #include "catalog/pg_proc.h" #include "catalog/pg_type.h" +#include "catalog/pg_variable.h" #include "commands/dbcommands.h" #include "miscadmin.h" #include "nodes/makefuncs.h" @@ -34,12 +35,14 @@ #include "parser/parse_relation.h" #include "parser/parse_target.h" #include "parser/parse_type.h" +#include "storage/lmgr.h" #include "utils/builtins.h" #include "utils/date.h" #include "utils/fmgroids.h" #include "utils/jsonb.h" #include "utils/lsyscache.h" #include "utils/timestamp.h" +#include "utils/typcache.h" #include "utils/xml.h" /* GUC parameters */ @@ -108,6 +111,9 @@ static Expr *make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree, int location); static Node *make_nulltest_from_distinct(ParseState *pstate, A_Expr *distincta, Node *arg); +static Node *makeParamSessionVariable(ParseState *pstate, + Oid varid, Oid typid, int32 typmod, Oid collid, + char *attrname, int location); /* @@ -501,6 +507,89 @@ transformIndirection(ParseState *pstate, A_Indirection *ind) return result; } +/* + * Returns true if the given expression kind is valid for session variables. + * Session variables can be used everywhere where external parameters can be + * used. Session variables are not allowed in DDL commands or in constraints. + * + * An identifier can be parsed as a session variable only for expression kinds + * where session variables are allowed. This is the primary usage of this + * function. + * + * The second usage of this function is to decide whether a "column does not + * exist" or a "column or variable does not exist" error message should be + * printed. When we are in an expression where session variables cannot be + * used, we raise the first form of error message. + */ +static bool +expr_kind_allows_session_variables(ParseExprKind p_expr_kind) +{ + bool result = false; + + switch (p_expr_kind) + { + case EXPR_KIND_NONE: + Assert(false); /* can't happen */ + return false; + + /* session variables allowed */ + case EXPR_KIND_OTHER: + case EXPR_KIND_JOIN_ON: + case EXPR_KIND_FROM_SUBSELECT: + case EXPR_KIND_FROM_FUNCTION: + case EXPR_KIND_WHERE: + case EXPR_KIND_HAVING: + case EXPR_KIND_FILTER: + case EXPR_KIND_WINDOW_PARTITION: + case EXPR_KIND_WINDOW_ORDER: + case EXPR_KIND_WINDOW_FRAME_RANGE: + case EXPR_KIND_WINDOW_FRAME_ROWS: + case EXPR_KIND_WINDOW_FRAME_GROUPS: + case EXPR_KIND_SELECT_TARGET: + case EXPR_KIND_INSERT_TARGET: + case EXPR_KIND_UPDATE_SOURCE: + case EXPR_KIND_UPDATE_TARGET: + case EXPR_KIND_MERGE_WHEN: + case EXPR_KIND_MERGE_RETURNING: + case EXPR_KIND_GROUP_BY: + case EXPR_KIND_ORDER_BY: + case EXPR_KIND_DISTINCT_ON: + case EXPR_KIND_LIMIT: + case EXPR_KIND_OFFSET: + case EXPR_KIND_RETURNING: + case EXPR_KIND_VALUES: + case EXPR_KIND_VALUES_SINGLE: + case EXPR_KIND_ALTER_COL_TRANSFORM: + case EXPR_KIND_EXECUTE_PARAMETER: + case EXPR_KIND_POLICY: + case EXPR_KIND_CALL_ARGUMENT: + case EXPR_KIND_COPY_WHERE: + case EXPR_KIND_LET_TARGET: + result = true; + break; + + /* session variables not allowed */ + case EXPR_KIND_CHECK_CONSTRAINT: + case EXPR_KIND_DOMAIN_CHECK: + case EXPR_KIND_COLUMN_DEFAULT: + case EXPR_KIND_FUNCTION_DEFAULT: + case EXPR_KIND_INDEX_EXPRESSION: + case EXPR_KIND_INDEX_PREDICATE: + case EXPR_KIND_STATS_EXPRESSION: + case EXPR_KIND_TRIGGER_WHEN: + case EXPR_KIND_PARTITION_BOUND: + case EXPR_KIND_PARTITION_EXPRESSION: + case EXPR_KIND_GENERATED_COLUMN: + case EXPR_KIND_JOIN_USING: + case EXPR_KIND_CYCLE_MARK: + case EXPR_KIND_ASSIGN_TARGET: + result = false; + break; + } + + return result; +} + /* * Transform a ColumnRef. * @@ -577,6 +666,8 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) case EXPR_KIND_COPY_WHERE: case EXPR_KIND_GENERATED_COLUMN: case EXPR_KIND_CYCLE_MARK: + case EXPR_KIND_ASSIGN_TARGET: + case EXPR_KIND_LET_TARGET: /* okay */ break; @@ -849,8 +940,61 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) } /* - * Throw error if no translation found. + * There are contexts where session variables are not allowed. We don't + * need to identify session variables in such a context, but identifying + * them allows us to raise meaningful error messages like "you cannot use + * session variables here". */ + if (expr_kind_allows_session_variables(pstate->p_expr_kind)) + { + Oid varid = InvalidOid; + char *attrname = NULL; + bool not_unique; + + /* ----- + * Session variables are shadowed by columns, routine variables or + * routine arguments. We certainly don't want to use a session variable + * when it is exactly shadowed, but a RTE like this is conceivable: + * + * CREATE TYPE t AS (c int); + * CREATE VARIABLE foo AS t; + * CREATE TABLE foo(a int, b int); + * + * SELECT foo.a, foo.b, foo.c FROM foo; + * + * However, that is very confusing, so we disallow it. We don't try to + * identify a variable if we know that it would be shadowed. + * ----- + */ + if (!node && !(relname && crerr == CRERR_NO_COLUMN)) + { + /* takes an AccessShareLock on the session variable */ + varid = IdentifyVariable(cref->fields, &attrname, ¬_unique, false); + + if (OidIsValid(varid)) + { + Oid typid; + int32 typmod; + Oid collid; + + if (not_unique) + ereport(ERROR, + (errcode(ERRCODE_AMBIGUOUS_PARAMETER), + errmsg("session variable reference \"%s\" is ambiguous", + NameListToString(cref->fields)), + parser_errposition(pstate, cref->location))); + + get_session_variable_type_typmod_collid(varid, &typid, &typmod, + &collid); + + node = makeParamSessionVariable(pstate, + varid, typid, typmod, collid, + attrname, cref->location); + } + } + } + + /* throw an error if no translation was found */ if (node == NULL) { switch (crerr) @@ -882,6 +1026,72 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) return node; } +/* + * Generate param variable for reference to session variable + */ +static Node * +makeParamSessionVariable(ParseState *pstate, + Oid varid, Oid typid, int32 typmod, Oid collid, + char *attrname, int location) +{ + Param *param; + + param = makeNode(Param); + + param->paramkind = PARAM_VARIABLE; + param->paramvarid = varid; + param->paramtype = typid; + param->paramtypmod = typmod; + param->paramcollid = collid; + + pstate->p_hasSessionVariables = true; + + if (attrname != NULL) + { + TupleDesc tupdesc; + int i; + + tupdesc = lookup_rowtype_tupdesc_noerror(typid, typmod, true); + if (!tupdesc) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("variable \"%s.%s\" is of type \"%s\", which is not a composite type", + get_namespace_name(get_session_variable_namespace(varid)), + get_session_variable_name(varid), + format_type_be(typid)), + parser_errposition(pstate, location))); + + for (i = 0; i < tupdesc->natts; i++) + { + Form_pg_attribute att = TupleDescAttr(tupdesc, i); + + if (strcmp(attrname, NameStr(att->attname)) == 0 && + !att->attisdropped) + { + /* success, so generate a FieldSelect expression */ + FieldSelect *fselect = makeNode(FieldSelect); + + fselect->arg = (Expr *) param; + fselect->fieldnum = i + 1; + fselect->resulttype = att->atttypid; + fselect->resulttypmod = att->atttypmod; + /* save attribute's collation for parse_collate.c */ + fselect->resultcollid = att->attcollation; + + ReleaseTupleDesc(tupdesc); + return (Node *) fselect; + } + } + + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_COLUMN), + errmsg("could not identify column \"%s\" in variable", attrname), + parser_errposition(pstate, location))); + } + + return (Node *) param; +} + static Node * transformParamRef(ParseState *pstate, ParamRef *pref) { @@ -1817,6 +2027,7 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_VALUES: case EXPR_KIND_VALUES_SINGLE: case EXPR_KIND_CYCLE_MARK: + case EXPR_KIND_LET_TARGET: /* okay */ break; case EXPR_KIND_CHECK_CONSTRAINT: @@ -1860,6 +2071,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_GENERATED_COLUMN: err = _("cannot use subquery in column generation expression"); break; + case EXPR_KIND_ASSIGN_TARGET: + err = _("cannot use subquery as target of assign statement"); + break; /* * There is intentionally no default: case here, so that the @@ -3199,6 +3413,10 @@ ParseExprKindName(ParseExprKind exprKind) return "GENERATED AS"; case EXPR_KIND_CYCLE_MARK: return "CYCLE"; + case EXPR_KIND_ASSIGN_TARGET: + return "ASSIGN"; + case EXPR_KIND_LET_TARGET: + return "LET"; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c index 9b23344a3b1..9aa4f60768b 100644 --- a/src/backend/parser/parse_func.c +++ b/src/backend/parser/parse_func.c @@ -2656,6 +2656,8 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location) err = _("set-returning functions are not allowed in column generation expressions"); break; case EXPR_KIND_CYCLE_MARK: + case EXPR_KIND_ASSIGN_TARGET: + case EXPR_KIND_LET_TARGET: errkind = true; break; diff --git a/src/backend/tcop/dest.c b/src/backend/tcop/dest.c index 96f80b30463..dac78ba5cce 100644 --- a/src/backend/tcop/dest.c +++ b/src/backend/tcop/dest.c @@ -38,6 +38,7 @@ #include "executor/functions.h" #include "executor/tqueue.h" #include "executor/tstoreReceiver.h" +#include "executor/svariableReceiver.h" #include "libpq/libpq.h" #include "libpq/pqformat.h" @@ -155,6 +156,9 @@ CreateDestReceiver(CommandDest dest) case DestExplainSerialize: return CreateExplainSerializeDestReceiver(NULL); + + case DestVariable: + return CreateVariableDestReceiver(InvalidOid); } /* should never get here */ @@ -191,6 +195,7 @@ EndCommand(const QueryCompletion *qc, CommandDest dest, bool force_undecorated_o case DestTransientRel: case DestTupleQueue: case DestExplainSerialize: + case DestVariable: break; } } @@ -237,6 +242,7 @@ NullCommand(CommandDest dest) case DestTransientRel: case DestTupleQueue: case DestExplainSerialize: + case DestVariable: break; } } @@ -281,6 +287,7 @@ ReadyForQuery(CommandDest dest) case DestTransientRel: case DestTupleQueue: case DestExplainSerialize: + case DestVariable: break; } } diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c index a1f8d03db1e..ef31b1881b1 100644 --- a/src/backend/tcop/pquery.c +++ b/src/backend/tcop/pquery.c @@ -86,6 +86,9 @@ CreateQueryDesc(PlannedStmt *plannedstmt, qd->queryEnv = queryEnv; qd->instrument_options = instrument_options; /* instrumentation wanted? */ + qd->num_session_variables = 0; + qd->session_variables = NULL; + /* null these fields until set by ExecutorStart */ qd->tupDesc = NULL; qd->estate = NULL; diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c index 45af3877ea9..bdac691af13 100644 --- a/src/backend/tcop/utility.c +++ b/src/backend/tcop/utility.c @@ -49,6 +49,7 @@ #include "commands/schemacmds.h" #include "commands/seclabel.h" #include "commands/sequence.h" +#include "commands/session_variable.h" #include "commands/subscriptioncmds.h" #include "commands/tablecmds.h" #include "commands/tablespace.h" @@ -235,6 +236,7 @@ ClassifyUtilityCommandAsReadOnly(Node *parsetree) case T_CallStmt: case T_DoStmt: + case T_LetStmt: { /* * Commands inside the DO block or the called procedure might @@ -1064,6 +1066,11 @@ standard_ProcessUtility(PlannedStmt *pstmt, break; } + case T_LetStmt: + ExecuteLetStmt(pstate, (LetStmt *) parsetree, params, + queryEnv, qc); + break; + default: /* All other statement types have event trigger support */ ProcessUtilitySlow(pstate, pstmt, queryString, @@ -2203,6 +2210,10 @@ UtilityContainsQuery(Node *parsetree) return UtilityContainsQuery(qry->utilityStmt); return qry; + case T_LetStmt: + qry = castNode(Query, ((LetStmt *) parsetree)->query); + return qry; + default: return NULL; } @@ -2401,6 +2412,10 @@ CreateCommandTag(Node *parsetree) tag = CMDTAG_SELECT; break; + case T_LetStmt: + tag = CMDTAG_LET; + break; + /* utility statements --- same whether raw or cooked */ case T_TransactionStmt: { @@ -3286,6 +3301,7 @@ GetCommandLogLevel(Node *parsetree) break; case T_PLAssignStmt: + case T_LetStmt: lev = LOGSTMT_ALL; break; diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index badbf111ee0..f90467d684b 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -37,6 +37,7 @@ #include "catalog/pg_statistic_ext.h" #include "catalog/pg_trigger.h" #include "catalog/pg_type.h" +#include "catalog/pg_variable.h" #include "commands/defrem.h" #include "commands/tablespace.h" #include "common/keywords.h" @@ -528,6 +529,7 @@ static char *generate_function_name(Oid funcid, int nargs, static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2); static void add_cast_to(StringInfo buf, Oid typid); static char *generate_qualified_type_name(Oid typid); +static char *generate_session_variable_name(Oid varid); static text *string_to_text(char *str); static char *flatten_reloptions(Oid relid); static void get_reloptions(StringInfo buf, Datum reloptions); @@ -8590,6 +8592,14 @@ get_parameter(Param *param, deparse_context *context) return; } + /* translate paramvarid to session variable name */ + if (param->paramkind == PARAM_VARIABLE) + { + appendStringInfo(context->buf, "%s", + generate_session_variable_name(param->paramvarid)); + return; + } + /* * Alternatively, maybe it's a subplan output, which we print as a * reference to the subplan. (We could drill down into the subplan and @@ -13372,6 +13382,42 @@ generate_collation_name(Oid collid) return result; } +/* + * generate_session_variable_name + * Compute the name to display for a session variable specified by OID + * + * The result includes all necessary quoting and schema-prefixing. + */ +static char * +generate_session_variable_name(Oid varid) +{ + HeapTuple tup; + Form_pg_variable varform; + char *varname; + char *nspname; + char *result; + + tup = SearchSysCache1(VARIABLEOID, ObjectIdGetDatum(varid)); + + if (!HeapTupleIsValid(tup)) + elog(ERROR, "cache lookup failed for variable %u", varid); + + varform = (Form_pg_variable) GETSTRUCT(tup); + + varname = NameStr(varform->varname); + + if (!VariableIsVisible(varid)) + nspname = get_namespace_name_or_temp(varform->varnamespace); + else + nspname = NULL; + + result = quote_qualified_identifier(nspname, varname); + + ReleaseSysCache(tup); + + return result; +} + /* * Given a C string, produce a TEXT datum. * diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c index 5af1a168ec2..7e1e9e28f12 100644 --- a/src/backend/utils/cache/plancache.c +++ b/src/backend/utils/cache/plancache.c @@ -58,6 +58,7 @@ #include "access/transam.h" #include "catalog/namespace.h" +#include "catalog/pg_variable.h" #include "executor/executor.h" #include "miscadmin.h" #include "nodes/nodeFuncs.h" @@ -162,6 +163,7 @@ InitPlanCache(void) CacheRegisterSyscacheCallback(AMOPOPID, PlanCacheSysCallback, (Datum) 0); CacheRegisterSyscacheCallback(FOREIGNSERVEROID, PlanCacheSysCallback, (Datum) 0); CacheRegisterSyscacheCallback(FOREIGNDATAWRAPPEROID, PlanCacheSysCallback, (Datum) 0); + CacheRegisterSyscacheCallback(VARIABLEOID, PlanCacheObjectCallback, (Datum) 0); } /* @@ -1903,18 +1905,33 @@ ScanQueryForLocks(Query *parsetree, bool acquire) /* * Recurse into sublink subqueries, too. But we already did the ones in - * the rtable and cteList. + * the rtable and cteList. We need to force a recursive call for session + * variables too, to find and lock variables used in the query (see + * ScanQueryWalker). */ - if (parsetree->hasSubLinks) + if (parsetree->hasSubLinks || + parsetree->hasSessionVariables) { query_tree_walker(parsetree, ScanQueryWalker, (void *) &acquire, QTW_IGNORE_RC_SUBQUERIES); } + + /* process session variables */ + if (OidIsValid(parsetree->resultVariable)) + { + if (acquire) + LockDatabaseObject(VariableRelationId, parsetree->resultVariable, + 0, AccessShareLock); + else + UnlockDatabaseObject(VariableRelationId, parsetree->resultVariable, + 0, AccessShareLock); + } } /* - * Walker to find sublink subqueries for ScanQueryForLocks + * Walker to find sublink subqueries or referenced session variables + * for ScanQueryForLocks */ static bool ScanQueryWalker(Node *node, bool *acquire) @@ -1929,6 +1946,20 @@ ScanQueryWalker(Node *node, bool *acquire) ScanQueryForLocks(castNode(Query, sub->subselect), *acquire); /* Fall through to process lefthand args of SubLink */ } + else if (IsA(node, Param)) + { + Param *p = (Param *) node; + + if (p->paramkind == PARAM_VARIABLE) + { + if (acquire) + LockDatabaseObject(VariableRelationId, p->paramvarid, + 0, AccessShareLock); + else + UnlockDatabaseObject(VariableRelationId, p->paramvarid, + 0, AccessShareLock); + } + } /* * Do NOT recurse into Query nodes, because ScanQueryForLocks already @@ -2060,7 +2091,9 @@ PlanCacheRelCallback(Datum arg, Oid relid) /* * PlanCacheObjectCallback - * Syscache inval callback function for PROCOID and TYPEOID caches + * Syscache inval callback function for TYPEOID, PROCOID, NAMESPACEOID, + * OPEROID, AMOPOPID, FOREIGNSERVEROID, FOREIGNDATAWRAPPEROID and + * VARIABLEOID caches. * * Invalidate all plans mentioning the object with the specified hash value, * or all plans mentioning any member of this cache if hashvalue == 0. diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c index e48a86be54b..eaae0c5a933 100644 --- a/src/backend/utils/fmgr/fmgr.c +++ b/src/backend/utils/fmgr/fmgr.c @@ -2026,9 +2026,13 @@ get_call_expr_arg_stable(Node *expr, int argnum) */ if (IsA(arg, Const)) return true; - if (IsA(arg, Param) && - ((Param *) arg)->paramkind == PARAM_EXTERN) - return true; + if (IsA(arg, Param)) + { + Param *p = (Param *) arg; + + if (p->paramkind == PARAM_EXTERN || p->paramkind == PARAM_VARIABLE) + return true; + } return false; } diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c index baae5965133..db0e9cd3618 100644 --- a/src/bin/psql/tab-complete.c +++ b/src/bin/psql/tab-complete.c @@ -1709,8 +1709,8 @@ psql_completion(const char *text, int start, int end) "ABORT", "ALTER", "ANALYZE", "BEGIN", "CALL", "CHECKPOINT", "CLOSE", "CLUSTER", "COMMENT", "COMMIT", "COPY", "CREATE", "DEALLOCATE", "DECLARE", "DELETE FROM", "DISCARD", "DO", "DROP", "END", "EXECUTE", "EXPLAIN", - "FETCH", "GRANT", "IMPORT FOREIGN SCHEMA", "INSERT INTO", "LISTEN", "LOAD", "LOCK", - "MERGE INTO", "MOVE", "NOTIFY", "PREPARE", + "FETCH", "GRANT", "IMPORT FOREIGN SCHEMA", "INSERT INTO", "LET", + "LISTEN", "LOAD", "LOCK", "MERGE INTO", "MOVE", "NOTIFY", "PREPARE", "REASSIGN", "REFRESH MATERIALIZED VIEW", "REINDEX", "RELEASE", "RESET", "REVOKE", "ROLLBACK", "SAVEPOINT", "SECURITY LABEL", "SELECT", "SET", "SHOW", "START", @@ -4268,6 +4268,14 @@ psql_completion(const char *text, int start, int end) else if (TailMatches("VALUES") && !TailMatches("DEFAULT", "VALUES")) COMPLETE_WITH("("); +/* LET */ + /* If prev. word is LET suggest a list of variables */ + else if (Matches("LET")) + COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_variables); + /* Complete LET with "=" */ + else if (TailMatches("LET", MatchAny)) + COMPLETE_WITH("="); + /* LOCK */ /* Complete LOCK [TABLE] [ONLY] with a list of tables */ else if (Matches("LOCK")) diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h index 18ea6ac83a5..def691dafb3 100644 --- a/src/include/catalog/namespace.h +++ b/src/include/catalog/namespace.h @@ -171,7 +171,9 @@ extern SearchPathMatcher *GetSearchPathMatcher(MemoryContext context); extern SearchPathMatcher *CopySearchPathMatcher(SearchPathMatcher *path); extern bool SearchPathMatchesCurrentEnvironment(SearchPathMatcher *path); +extern List *NamesFromList(List *names); extern Oid LookupVariable(const char *nspname, const char *varname, bool missing_ok); +extern Oid IdentifyVariable(List *names, char **attrname, bool *not_unique, bool noerror); extern Oid get_collation_oid(List *collname, bool missing_ok); extern Oid get_conversion_oid(List *conname, bool missing_ok); diff --git a/src/include/catalog/pg_variable.h b/src/include/catalog/pg_variable.h index 3810e040f28..db593cd5bed 100644 --- a/src/include/catalog/pg_variable.h +++ b/src/include/catalog/pg_variable.h @@ -35,6 +35,14 @@ CATALOG(pg_variable,9222,VariableRelationId) /* OID of entry in pg_type for variable's type */ Oid vartype BKI_LOOKUP(pg_type); + /* + * Used for identity check [oid, create_lsn]. + * + * This column of the 8-byte XlogRecPtr type should be at an address that + * is divisible by 8, but before any column of type NameData. + */ + XLogRecPtr varcreate_lsn; + /* variable name */ NameData varname; diff --git a/src/include/commands/session_variable.h b/src/include/commands/session_variable.h new file mode 100644 index 00000000000..b3f03c65827 --- /dev/null +++ b/src/include/commands/session_variable.h @@ -0,0 +1,32 @@ +/*------------------------------------------------------------------------- + * + * sessionvariable.h + * prototypes for sessionvariable.c. + * + * + * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/commands/session_variable.h + * + *------------------------------------------------------------------------- + */ + +#ifndef SESSIONVARIABLE_H +#define SESSIONVARIABLE_H + +#include "nodes/params.h" +#include "nodes/parsenodes.h" +#include "parser/parse_node.h" +#include "tcop/cmdtag.h" +#include "utils/queryenvironment.h" + +extern void SetSessionVariable(Oid varid, Datum value, bool isNull); +extern void SetSessionVariableWithSecurityCheck(Oid varid, Datum value, bool isNull); +extern Datum GetSessionVariable(Oid varid, bool *isNull, Oid *typid); +extern Datum GetSessionVariableWithTypeCheck(Oid varid, bool *isNull, Oid expected_typid); + +extern void ExecuteLetStmt(ParseState *pstate, LetStmt *stmt, ParamListInfo params, + QueryEnvironment *queryEnv, QueryCompletion *qc); + +#endif diff --git a/src/include/executor/execdesc.h b/src/include/executor/execdesc.h index 0a7274e26c8..d1b2f59e0cf 100644 --- a/src/include/executor/execdesc.h +++ b/src/include/executor/execdesc.h @@ -48,6 +48,10 @@ typedef struct QueryDesc EState *estate; /* executor's query-wide state */ PlanState *planstate; /* tree of per-plan-node state */ + /* reference to session variables buffer */ + int num_session_variables; + SessionVariableValue *session_variables; + /* This field is set by ExecutorRun */ bool already_executed; /* true if previously executed */ diff --git a/src/include/executor/svariableReceiver.h b/src/include/executor/svariableReceiver.h new file mode 100644 index 00000000000..db44d8b94c6 --- /dev/null +++ b/src/include/executor/svariableReceiver.h @@ -0,0 +1,22 @@ +/*------------------------------------------------------------------------- + * + * svariableReceiver.h + * prototypes for svariableReceiver.c + * + * + * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/executor/svariableReceiver.h + * + *------------------------------------------------------------------------- + */ + +#ifndef SVARIABLE_RECEIVER_H +#define SVARIABLE_RECEIVER_H + +#include "tcop/dest.h" + +extern DestReceiver *CreateVariableDestReceiver(Oid varid); + +#endif /* SVARIABLE_RECEIVER_H */ diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 516b9487435..82847fa6e5a 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -613,6 +613,18 @@ typedef struct AsyncRequest * tuples) */ } AsyncRequest; +/* ---------------- + * SessionVariableValue + * ---------------- + */ +typedef struct SessionVariableValue +{ + Oid varid; + Oid typid; + bool isnull; + Datum value; +} SessionVariableValue; + /* ---------------- * EState information * @@ -665,6 +677,10 @@ typedef struct EState ParamListInfo es_param_list_info; /* values of external params */ ParamExecData *es_param_exec_vals; /* values of internal params */ + /* Session variables info: */ + int es_num_session_variables; /* number of used variables */ + SessionVariableValue *es_session_variables; /* array of copies of values */ + QueryEnvironment *es_queryEnv; /* query environment */ /* Other working state: */ diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 6ea52818897..7c1ad5146d0 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -142,6 +142,9 @@ typedef struct Query */ int resultRelation pg_node_attr(query_jumble_ignore); + /* target variable of LET statement */ + Oid resultVariable; + /* has aggregates in tlist or havingQual */ bool hasAggs pg_node_attr(query_jumble_ignore); /* has window functions in tlist */ @@ -162,6 +165,8 @@ typedef struct Query bool hasRowSecurity pg_node_attr(query_jumble_ignore); /* parser has added an RTE_GROUP RTE */ bool hasGroupRTE pg_node_attr(query_jumble_ignore); + /* uses session variables */ + bool hasSessionVariables pg_node_attr(query_jumble_ignore); /* is a RETURN statement */ bool isReturn pg_node_attr(query_jumble_ignore); @@ -2091,6 +2096,18 @@ typedef struct MergeStmt WithClause *withClause; /* WITH clause */ } MergeStmt; +/* ---------------------- + * Let Statement + * ---------------------- + */ +typedef struct LetStmt +{ + NodeTag type; + List *target; /* target variable */ + Node *query; /* source expression */ + int location; +} LetStmt; + /* ---------------------- * Select Statement * diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h index 07e2415398e..7a90ade4282 100644 --- a/src/include/nodes/pathnodes.h +++ b/src/include/nodes/pathnodes.h @@ -163,6 +163,9 @@ typedef struct PlannerGlobal /* partition descriptors */ PartitionDirectory partition_directory pg_node_attr(read_write_ignore); + + /* list of used session variables */ + List *sessionVariables; } PlannerGlobal; /* macro for fetching the Plan associated with a SubPlan node */ @@ -508,6 +511,8 @@ struct PlannerInfo bool placeholdersFrozen; /* true if planning a recursive WITH item */ bool hasRecursion; + /* true if session variables were used */ + bool hasSessionVariables; /* * The rangetable index for the RTE_GROUP RTE, or 0 if there is no diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h index 62cd6a6666e..18493b2c4e9 100644 --- a/src/include/nodes/plannodes.h +++ b/src/include/nodes/plannodes.h @@ -49,7 +49,7 @@ typedef struct PlannedStmt NodeTag type; - CmdType commandType; /* select|insert|update|delete|merge|utility */ + CmdType commandType; /* select|let|insert|update|delete|merge|utility */ uint64 queryId; /* query identifier (copied from Query) */ @@ -94,6 +94,8 @@ typedef struct PlannedStmt Node *utilityStmt; /* non-null if this is utility stmt */ + List *sessionVariables; /* OIDs for PARAM_VARIABLE Params */ + /* statement location in source string (copied from Query) */ ParseLoc stmt_location; /* start location, or -1 if unknown */ ParseLoc stmt_len; /* length in bytes; 0 means "rest of string" */ diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h index ea47652adb8..5f7b83d13fa 100644 --- a/src/include/nodes/primnodes.h +++ b/src/include/nodes/primnodes.h @@ -361,6 +361,9 @@ typedef struct Const * of the `paramid' field contain the SubLink's subLinkId, and * the low-order 16 bits contain the column number. (This type * of Param is also converted to PARAM_EXEC during planning.) + * + * PARAM_VARIABLE: The parameter is a reference to a session variable + * (paramid holds the variable's OID). */ typedef enum ParamKind { @@ -368,6 +371,7 @@ typedef enum ParamKind PARAM_EXEC, PARAM_SUBLINK, PARAM_MULTIEXPR, + PARAM_VARIABLE, } ParamKind; typedef struct Param @@ -380,6 +384,8 @@ typedef struct Param int32 paramtypmod pg_node_attr(query_jumble_ignore); /* OID of collation, or InvalidOid if none */ Oid paramcollid pg_node_attr(query_jumble_ignore); + /* OID of session variable if it is used */ + Oid paramvarid; /* token location, or -1 if unknown */ ParseLoc location; } Param; diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h index aafc1737921..de471692e82 100644 --- a/src/include/optimizer/planmain.h +++ b/src/include/optimizer/planmain.h @@ -120,4 +120,6 @@ extern void record_plan_function_dependency(PlannerInfo *root, Oid funcid); extern void record_plan_type_dependency(PlannerInfo *root, Oid typid); extern bool extract_query_dependencies_walker(Node *node, PlannerInfo *context); +extern void pull_up_has_session_variables(PlannerInfo *root); + #endif /* PLANMAIN_H */ diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h index 964e27b577f..f90d3d43f7f 100644 --- a/src/include/parser/kwlist.h +++ b/src/include/parser/kwlist.h @@ -256,6 +256,7 @@ PG_KEYWORD("leading", LEADING, RESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("leakproof", LEAKPROOF, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("least", LEAST, COL_NAME_KEYWORD, BARE_LABEL) PG_KEYWORD("left", LEFT, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL) +PG_KEYWORD("let", LET, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("level", LEVEL, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("like", LIKE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL) PG_KEYWORD("limit", LIMIT, RESERVED_KEYWORD, AS_LABEL) diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h index 543df568147..d284d38b668 100644 --- a/src/include/parser/parse_node.h +++ b/src/include/parser/parse_node.h @@ -82,6 +82,8 @@ typedef enum ParseExprKind EXPR_KIND_COPY_WHERE, /* WHERE condition in COPY FROM */ EXPR_KIND_GENERATED_COLUMN, /* generation expression for a column */ EXPR_KIND_CYCLE_MARK, /* cycle mark value */ + EXPR_KIND_ASSIGN_TARGET, /* PL/pgSQL assignment target */ + EXPR_KIND_LET_TARGET, /* LET target */ } ParseExprKind; @@ -228,6 +230,7 @@ struct ParseState bool p_hasTargetSRFs; bool p_hasSubLinks; bool p_hasModifyingCTE; + bool p_hasSessionVariables; Node *p_last_srf; /* most recent set-returning func/op found */ diff --git a/src/include/tcop/cmdtaglist.h b/src/include/tcop/cmdtaglist.h index 9465df7b2ff..a921af2486f 100644 --- a/src/include/tcop/cmdtaglist.h +++ b/src/include/tcop/cmdtaglist.h @@ -186,6 +186,7 @@ PG_CMDTAG(CMDTAG_GRANT, "GRANT", true, false, false) PG_CMDTAG(CMDTAG_GRANT_ROLE, "GRANT ROLE", false, false, false) PG_CMDTAG(CMDTAG_IMPORT_FOREIGN_SCHEMA, "IMPORT FOREIGN SCHEMA", true, false, false) PG_CMDTAG(CMDTAG_INSERT, "INSERT", false, false, true) +PG_CMDTAG(CMDTAG_LET, "LET", false, false, false) PG_CMDTAG(CMDTAG_LISTEN, "LISTEN", false, false, false) PG_CMDTAG(CMDTAG_LOAD, "LOAD", false, false, false) PG_CMDTAG(CMDTAG_LOCK_TABLE, "LOCK TABLE", false, false, false) diff --git a/src/include/tcop/dest.h b/src/include/tcop/dest.h index a3d521b6f97..38cc87f4e7a 100644 --- a/src/include/tcop/dest.h +++ b/src/include/tcop/dest.h @@ -97,6 +97,7 @@ typedef enum DestTransientRel, /* results sent to transient relation */ DestTupleQueue, /* results sent to tuple queue */ DestExplainSerialize, /* results are serialized and discarded */ + DestVariable, /* results sent to session variable */ } CommandDest; /* ---------------- diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index ea9740e3f89..f76deb56d5a 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -8103,7 +8103,8 @@ exec_is_simple_query(PLpgSQL_expr *expr) query->sortClause || query->limitOffset || query->limitCount || - query->setOperations) + query->setOperations || + query->hasSessionVariables) return false; /* diff --git a/src/test/regress/expected/session_variables.out b/src/test/regress/expected/session_variables.out index aca766042db..16e1d01ddc6 100644 --- a/src/test/regress/expected/session_variables.out +++ b/src/test/regress/expected/session_variables.out @@ -55,3 +55,925 @@ SET ROLE TO DEFAULT; DROP VARIABLE svartest.var1; DROP SCHEMA svartest; DROP ROLE regress_variable_owner; +-- check access rights +CREATE ROLE regress_noowner; +CREATE VARIABLE var1 AS int; +CREATE OR REPLACE FUNCTION sqlfx(int) +RETURNS int AS $$ SELECT $1 + var1 $$ LANGUAGE sql; +CREATE OR REPLACE FUNCTION sqlfx_sd(int) +RETURNS int AS $$ SELECT $1 + var1 $$ LANGUAGE sql SECURITY DEFINER; +CREATE OR REPLACE FUNCTION plpgsqlfx(int) +RETURNS int AS $$ BEGIN RETURN $1 + var1; END $$ LANGUAGE plpgsql; +CREATE OR REPLACE FUNCTION plpgsqlfx_sd(int) +RETURNS int AS $$ BEGIN RETURN $1 + var1; END $$ LANGUAGE plpgsql SECURITY DEFINER; +LET var1 = 10; +-- should be ok +SELECT var1; + var1 +------ + 10 +(1 row) + +SELECT sqlfx(20); + sqlfx +------- + 30 +(1 row) + +SELECT sqlfx_sd(20); + sqlfx_sd +---------- + 30 +(1 row) + +SELECT plpgsqlfx(20); + plpgsqlfx +----------- + 30 +(1 row) + +SELECT plpgsqlfx_sd(20); + plpgsqlfx_sd +-------------- + 30 +(1 row) + +-- should fail +SET ROLE TO regress_noowner; +SELECT var1; +ERROR: permission denied for session variable var1 +SELECT sqlfx(20); +ERROR: permission denied for session variable var1 +CONTEXT: SQL function "sqlfx" statement 1 +SELECT plpgsqlfx(20); +ERROR: permission denied for session variable var1 +CONTEXT: SQL expression "$1 + var1" +PL/pgSQL function plpgsqlfx(integer) line 1 at RETURN +-- should be ok +SELECT sqlfx_sd(20); + sqlfx_sd +---------- + 30 +(1 row) + +SELECT plpgsqlfx_sd(20); + plpgsqlfx_sd +-------------- + 30 +(1 row) + +SET ROLE TO DEFAULT; +GRANT SELECT ON VARIABLE var1 TO regress_noowner; +-- should be ok +SET ROLE TO regress_noowner; +SELECT var1; + var1 +------ + 10 +(1 row) + +SELECT sqlfx(20); + sqlfx +------- + 30 +(1 row) + +SELECT plpgsqlfx(20); + plpgsqlfx +----------- + 30 +(1 row) + +SET ROLE TO DEFAULT; +DROP VARIABLE var1; +DROP FUNCTION sqlfx(int); +DROP FUNCTION plpgsqlfx(int); +DROP FUNCTION sqlfx_sd(int); +DROP FUNCTION plpgsqlfx_sd(int); +DROP ROLE regress_noowner; +-- use variables inside views +CREATE VARIABLE var1 AS numeric; +-- use variables in views +CREATE VIEW test_view AS SELECT COALESCE(var1 + v, 0) AS result FROM generate_series(1,2) g(v); +SELECT * FROM test_view; + result +-------- + 0 + 0 +(2 rows) + +LET var1 = 3.14; +SELECT * FROM test_view; + result +-------- + 4.14 + 5.14 +(2 rows) + +-- start a new session +\c +SELECT * FROM test_view; + result +-------- + 0 + 0 +(2 rows) + +LET var1 = 3.14; +SELECT * FROM test_view; + result +-------- + 4.14 + 5.14 +(2 rows) + +-- should fail, dependency +DROP VARIABLE var1; +ERROR: cannot drop session variable var1 because other objects depend on it +DETAIL: view test_view depends on session variable var1 +HINT: Use DROP ... CASCADE to drop the dependent objects too. +-- should be ok +DROP VARIABLE var1 CASCADE; +NOTICE: drop cascades to view test_view +CREATE VARIABLE var1 text; +CREATE VARIABLE var2 text; +-- use variables in SQL functions +CREATE OR REPLACE FUNCTION sqlfx1(varchar) +RETURNS varchar AS $$ SELECT var1 || ', ' || $1 $$ LANGUAGE sql; +CREATE OR REPLACE FUNCTION sqlfx2( varchar) +RETURNS varchar AS $$ SELECT var2 || ', ' || $1 $$ LANGUAGE sql; +LET var1 = 'str1'; +LET var2 = 'str2'; +SELECT sqlfx1(sqlfx2('Hello')); + sqlfx1 +------------------- + str1, str2, Hello +(1 row) + +-- inlining is blocked +EXPLAIN (COSTS OFF, VERBOSE) SELECT sqlfx1(sqlfx2('Hello')); + QUERY PLAN +------------------------------------------------------ + Result + Output: sqlfx1(sqlfx2('Hello'::character varying)) +(2 rows) + +DROP FUNCTION sqlfx1(varchar); +DROP FUNCTION sqlfx2(varchar); +DROP VARIABLE var1; +DROP VARIABLE var2; +-- access from cached plans should work +CREATE VARIABLE var1 AS numeric; +CREATE OR REPLACE FUNCTION plpgsqlfx() +RETURNS numeric AS $$ BEGIN RETURN var1; END $$ LANGUAGE plpgsql; +set plan_cache_mode TO force_generic_plan; +LET var1 = 3.14; +SELECT plpgsqlfx(); + plpgsqlfx +----------- + 3.14 +(1 row) + +LET var1 = 3.14 * 2; +SELECT plpgsqlfx(); + plpgsqlfx +----------- + 6.28 +(1 row) + +DROP VARIABLE var1; +-- dependency (plan invalidation) should work +CREATE VARIABLE var1 AS numeric; +LET var1 = 3.14 * 3; +SELECT plpgsqlfx(); + plpgsqlfx +----------- + 9.42 +(1 row) + +LET var1 = 3.14 * 4; +SELECT plpgsqlfx(); + plpgsqlfx +----------- + 12.56 +(1 row) + +DROP VARIABLE var1; +DROP FUNCTION plpgsqlfx(); +set plan_cache_mode TO DEFAULT; +-- usage LET statement in plpgsql should work +CREATE VARIABLE var1 int; +CREATE VARIABLE var2 numeric[]; +DO $$ +BEGIN + LET var2 = '{}'::int[]; + FOR i IN 1..10 + LOOP + LET var1 = i; + LET var2[var1] = i; + END LOOP; + RAISE NOTICE 'result array: %', var2; +END; +$$; +NOTICE: result array: {1,2,3,4,5,6,7,8,9,10} +DROP VARIABLE var1; +DROP VARIABLE var2; +-- CALL statement is not supported yet +-- requires direct access to session variable from expression executor +CREATE VARIABLE v int; +CREATE PROCEDURE p(arg int) AS $$ BEGIN RAISE NOTICE '%', arg; END $$ LANGUAGE plpgsql; +-- should not crash (but is not supported yet) +CALL p(v); +ERROR: session variable cannot be used as an argument +DO $$ BEGIN CALL p(v); END $$; +ERROR: session variable cannot be used as an argument +CONTEXT: SQL statement "CALL p(v)" +PL/pgSQL function inline_code_block line 1 at CALL +DROP PROCEDURE p(int); +DROP VARIABLE v; +-- EXECUTE statement is not supported yet +-- requires direct access to session variable from expression executor +CREATE VARIABLE v int; +LET v = 20; +PREPARE ptest(int) AS SELECT $1; +-- should fail +EXECUTE ptest(v); +ERROR: session variable cannot be used as an argument +DEALLOCATE ptest; +DROP VARIABLE v; +-- test search path +CREATE SCHEMA svartest; +CREATE VARIABLE svartest.var1 AS numeric; +-- should fail +LET var1 = pi(); +ERROR: session variable "var1" doesn't exist +LINE 1: LET var1 = pi(); + ^ +SELECT var1; +ERROR: column "var1" does not exist +LINE 1: SELECT var1; + ^ +-- should be ok +LET svartest.var1 = pi(); +SELECT svartest.var1; + var1 +------------------ + 3.14159265358979 +(1 row) + +SET search_path TO svartest; +-- should be ok +LET var1 = pi() + 10; +SELECT var1; + var1 +------------------ + 13.1415926535898 +(1 row) + +RESET search_path; +DROP SCHEMA svartest CASCADE; +NOTICE: drop cascades to session variable svartest.var1 +CREATE VARIABLE var1 AS text; +-- variables can be updated under RO transaction +BEGIN; +SET TRANSACTION READ ONLY; +LET var1 = 'hello'; +COMMIT; +SELECT var1; + var1 +------- + hello +(1 row) + +DROP VARIABLE var1; +-- test of domains +CREATE DOMAIN int_domain AS int NOT NULL CHECK (VALUE > 100); +CREATE VARIABLE var1 AS int_domain; +-- should fail +SELECT var1; +ERROR: domain int_domain does not allow null values +-- should be ok +LET var1 = 1000; +SELECT var1; + var1 +------ + 1000 +(1 row) + +-- should fail +LET var1 = 10; +ERROR: value for domain int_domain violates check constraint "int_domain_check" +-- should fail +LET var1 = NULL; +ERROR: domain int_domain does not allow null values +-- note - domain defaults are not supported yet (like PLpgSQL) +DROP VARIABLE var1; +DROP DOMAIN int_domain; +-- the expression should remain "unknown" +CREATE VARIABLE var1 AS int4multirange[]; +-- should be ok +LET var1 = NULL; +LET var1 = '{"{[2,8),[11,14)}","{[5,8),[12,14)}"}'; +LET var1[2] = '{[5,8),[12,100)}'; +SELECT var1; + var1 +---------------------------------------- + {"{[2,8),[11,14)}","{[5,8),[12,100)}"} +(1 row) + +--It should work in plpgsql too +DO $$ +BEGIN + LET var1 = NULL; + LET var1 = '{"{[2,8),[11,14)}","{[5,8),[12,14)}"}'; + LET var1[2] = '{[5,8),[12,100)}'; + + RAISE NOTICE '%', var1; +END; +$$; +NOTICE: {"{[2,8),[11,14)}","{[5,8),[12,100)}"} +DROP VARIABLE var1; +CREATE SCHEMA svartest CREATE VARIABLE var1 AS int CREATE TABLE foo(a int); +LET svartest.var1 = 100; +SELECT svartest.var1; + var1 +------ + 100 +(1 row) + +SET search_path to public, svartest; +SELECT var1; + var1 +------ + 100 +(1 row) + +DROP SCHEMA svartest CASCADE; +NOTICE: drop cascades to 2 other objects +DETAIL: drop cascades to table foo +drop cascades to session variable var1 +CREATE VARIABLE var1 AS int; +CREATE VARIABLE var2 AS int[]; +LET var1 = 2; +LET var2 = '{}'::int[]; +LET var2[var1] = 0; +SELECT var2; + var2 +----------- + [2:2]={0} +(1 row) + +DROP VARIABLE var1, var2; +CREATE VARIABLE var1 AS int; +CREATE VARIABLE var2 AS int[]; +LET var1 = 2; +LET var2 = '{}'::int[]; +SELECT var2; + var2 +------ + {} +(1 row) + +DROP VARIABLE var1, var2; +-- the LET statement should be disallowed in CTE +CREATE VARIABLE var1 AS int; +WITH x AS (LET var1 = 100) SELECT * FROM x; +ERROR: syntax error at or near "LET" +LINE 1: WITH x AS (LET var1 = 100) SELECT * FROM x; + ^ +-- should be ok +LET var1 = generate_series(1, 1); +-- should fail +LET var1 = generate_series(1, 2); +ERROR: expression returned more than one row +LET var1 = generate_series(1, 0); +ERROR: expression returned no rows +DROP VARIABLE var1; +-- composite variables +CREATE TYPE sv_xyz AS (x int, y int, z numeric(10,2)); +CREATE VARIABLE v1 AS sv_xyz; +CREATE VARIABLE v2 AS sv_xyz; +LET v1 = (1, 2, 3.14); +LET v2 = (10, 20, 3.14 * 10); +-- should work too - there are prepared casts +LET v1 = (1, 2, 3); +SELECT v1; + v1 +------------ + (1,2,3.00) +(1 row) + +SELECT v2; + v2 +--------------- + (10,20,31.40) +(1 row) + +SELECT (v1).*; + x | y | z +---+---+------ + 1 | 2 | 3.00 +(1 row) + +SELECT (v2).*; + x | y | z +----+----+------- + 10 | 20 | 31.40 +(1 row) + +SELECT v1.x + v1.z; + ?column? +---------- + 4.00 +(1 row) + +SELECT v2.x + v2.z; + ?column? +---------- + 41.40 +(1 row) + +-- access to composite fields should be safe too +CREATE ROLE regress_var_test_role; +SET ROLE TO regress_var_test_role; +-- should fail +SELECT v2.x; +ERROR: permission denied for session variable v2 +SET ROLE TO DEFAULT; +DROP VARIABLE v1; +DROP VARIABLE v2; +DROP ROLE regress_var_test_role; +CREATE TYPE t1 AS (a int, b numeric, c text); +CREATE VARIABLE v1 AS t1; +LET v1 = (1, pi(), 'hello'); +SELECT v1; + v1 +---------------------------- + (1,3.14159265358979,hello) +(1 row) + +LET v1.b = 10.2222; +SELECT v1; + v1 +------------------- + (1,10.2222,hello) +(1 row) + +-- should fail, attribute doesn't exist +LET v1.x = 10; +ERROR: cannot assign to field "x" of column "v1" because there is no such column in data type t1 +LINE 1: LET v1.x = 10; + ^ +-- should fail, don't allow multi column query +LET v1 = (NULL::t1).*; +ERROR: assignment expression returned 3 columns +LINE 1: LET v1 = (NULL::t1).*; + ^ +-- allow DROP or ADD ATTRIBUTE on composite types +-- should be ok +ALTER TYPE t1 DROP ATTRIBUTE c; +SELECT v1; + v1 +------------- + (1,10.2222) +(1 row) + +-- should be ok +ALTER TYPE t1 ADD ATTRIBUTE c int; +SELECT v1; + v1 +-------------- + (1,10.2222,) +(1 row) + +LET v1 = (10, 10.3, 20); +SELECT v1; + v1 +-------------- + (10,10.3,20) +(1 row) + +-- should be ok +ALTER TYPE t1 DROP ATTRIBUTE b; +SELECT v1; + v1 +--------- + (10,20) +(1 row) + +-- should fail, disallow data type change +ALTER TYPE t1 ALTER ATTRIBUTE c TYPE int; +ERROR: cannot alter type "t1" because session variable "public.v1" uses it +DROP VARIABLE v1; +DROP TYPE t1; +-- the table type can be used as composite type too +CREATE TABLE svar_test(a int, b numeric, c date); +CREATE VARIABLE var1 AS svar_test; +LET var1 = (10, pi(), '2023-05-26'); +SELECT var1; + var1 +---------------------------------- + (10,3.14159265358979,05-26-2023) +(1 row) + +-- should fail due dependency +ALTER TABLE svar_test ALTER COLUMN a TYPE text; +ERROR: cannot alter table "svar_test" because session variable "public.var1" uses it +-- should fail +DROP TABLE svar_test; +ERROR: cannot drop table svar_test because other objects depend on it +DETAIL: session variable var1 depends on type svar_test +HINT: Use DROP ... CASCADE to drop the dependent objects too. +DROP VARIABLE var1; +DROP TABLE svar_test; +-- arrays are supported +CREATE VARIABLE var1 AS numeric[]; +LET var1 = ARRAY[1.1,2.1]; +LET var1[1] = 10.1; +SELECT var1; + var1 +------------ + {10.1,2.1} +(1 row) + +-- LET target doesn't allow srf, should fail +LET var1[generate_series(1,3)] = 100; +ERROR: set-returning functions are not allowed in LET +LINE 1: LET var1[generate_series(1,3)] = 100; + ^ +DROP VARIABLE var1; +-- arrays inside composite +CREATE TYPE t1 AS (a numeric, b numeric[]); +CREATE VARIABLE var1 AS t1; +LET var1 = (10.1, ARRAY[0.0, 0.0]); +LET var1.a = 10.2; +SELECT var1; + var1 +-------------------- + (10.2,"{0.0,0.0}") +(1 row) + +LET var1.b[1] = 10.3; +SELECT var1; + var1 +--------------------- + (10.2,"{10.3,0.0}") +(1 row) + +DROP VARIABLE var1; +DROP TYPE t1; +-- Encourage use of parallel plans +SET parallel_setup_cost = 0; +SET parallel_tuple_cost = 0; +SET min_parallel_table_scan_size = 0; +SET max_parallel_workers_per_gather = 2; +-- test on query with workers +CREATE TABLE svar_test(a int); +INSERT INTO svar_test SELECT * FROM generate_series(1,1000); +ANALYZE svar_test; +CREATE VARIABLE zero int; +LET zero = 0; +-- result should be 100 +SELECT count(*) FROM svar_test WHERE a%10 = zero; + count +------- + 100 +(1 row) + +-- parallel execution is not supported yet +EXPLAIN (COSTS OFF) SELECT count(*) FROM svar_test WHERE a%10 = zero; + QUERY PLAN +----------------------------------- + Aggregate + -> Seq Scan on svar_test + Filter: ((a % 10) = zero) +(3 rows) + +LET zero = (SELECT count(*) FROM svar_test); +-- result should be 1000 +SELECT zero; + zero +------ + 1000 +(1 row) + +DROP VARIABLE zero; +DROP TABLE svar_test; +RESET parallel_setup_cost; +RESET parallel_tuple_cost; +RESET min_parallel_table_scan_size; +RESET max_parallel_workers_per_gather; +-- the result of view should be same in parallel mode too +CREATE VARIABLE var1 AS int; +LET var1 = 10; +CREATE VIEW var1view AS SELECT COALESCE(var1, 0) AS result; +SELECT * FROM var1view; + result +-------- + 10 +(1 row) + +SET debug_parallel_query TO on; +SELECT * FROM var1view; + result +-------- + 10 +(1 row) + +SET debug_parallel_query TO off; +DROP VIEW var1view; +DROP VARIABLE var1; +CREATE VARIABLE varid int; +CREATE TABLE svar_test(id int, v int); +LET varid = 1; +INSERT INTO svar_test VALUES(varid, 100); +SELECT * FROM svar_test; + id | v +----+----- + 1 | 100 +(1 row) + +UPDATE svar_test SET v = 200 WHERE id = varid; +SELECT * FROM svar_test; + id | v +----+----- + 1 | 200 +(1 row) + +DELETE FROM svar_test WHERE id = varid; +SELECT * FROM svar_test; + id | v +----+--- +(0 rows) + +DROP TABLE svar_test; +DROP VARIABLE varid; +-- visibility check +-- variables should be shadowed always +CREATE VARIABLE var1 AS text; +SELECT var1.relname FROM pg_class var1 WHERE var1.relname = 'pg_class'; + relname +---------- + pg_class +(1 row) + +DROP VARIABLE var1; +CREATE TABLE xxtab(avar int); +INSERT INTO xxtab VALUES(333); +CREATE TYPE xxtype AS (avar int); +CREATE VARIABLE xxtab AS xxtype; +INSERT INTO xxtab VALUES(10); +-- it is ambiguous, but columns are preferred +SELECT xxtab.avar FROM xxtab; + avar +------ + 333 + 10 +(2 rows) + +-- should be ok +SELECT avar FROM xxtab; + avar +------ + 333 + 10 +(2 rows) + +CREATE VARIABLE public.avar AS int; +-- should be ok, see the table +SELECT avar FROM xxtab; + avar +------ + 333 + 10 +(2 rows) + +-- should be ok +SELECT public.avar FROM xxtab; + avar +------ + + +(2 rows) + +DROP VARIABLE xxtab; +SELECT xxtab.avar FROM xxtab; + avar +------ + 333 + 10 +(2 rows) + +DROP VARIABLE public.avar; +DROP TYPE xxtype; +DROP TABLE xxtab; +-- The variable can be shadowed by table or by alias +CREATE TYPE public.svar_type AS (a int, b int, c int); +CREATE VARIABLE public.svar AS public.svar_type; +CREATE TABLE public.svar(a int, b int); +INSERT INTO public.svar VALUES(10, 20); +LET public.svar = (100, 200, 300); +-- should be ok +-- show table +SELECT * FROM public.svar; + a | b +----+---- + 10 | 20 +(1 row) + +SELECT svar.a FROM public.svar; + a +---- + 10 +(1 row) + +SELECT svar.* FROM public.svar; + a | b +----+---- + 10 | 20 +(1 row) + +-- show variable +SELECT public.svar; + svar +--------------- + (100,200,300) +(1 row) + +SELECT public.svar.c; + c +----- + 300 +(1 row) + +SELECT (public.svar).*; + a | b | c +-----+-----+----- + 100 | 200 | 300 +(1 row) + +-- the variable is shadowed, raise error +SELECT public.svar.c FROM public.svar; +ERROR: column svar.c does not exist +LINE 1: SELECT public.svar.c FROM public.svar; + ^ +-- can be fixed by alias +SELECT public.svar.c FROM public.svar x; + c +----- + 300 +(1 row) + +SELECT svar.a FROM public.svar; + a +---- + 10 +(1 row) + +SELECT svar.* FROM public.svar; + a | b +----+---- + 10 | 20 +(1 row) + +-- show variable +SELECT public.svar; + svar +--------------- + (100,200,300) +(1 row) + +SELECT public.svar.c; + c +----- + 300 +(1 row) + +SELECT (public.svar).*; + a | b | c +-----+-----+----- + 100 | 200 | 300 +(1 row) + +-- the variable is shadowed, raise error +SELECT public.svar.c FROM public.svar; +ERROR: column svar.c does not exist +LINE 1: SELECT public.svar.c FROM public.svar; + ^ +-- can be fixed by alias +SELECT public.svar.c FROM public.svar x; + c +----- + 300 +(1 row) + +DROP VARIABLE public.svar; +DROP TABLE public.svar; +DROP TYPE public.svar_type; +CREATE TYPE ab AS (a integer, b integer); +CREATE VARIABLE v_ab AS ab; +CREATE TABLE v_ab (a integer, b integer); +INSERT INTO v_ab VALUES(10,20); +-- we should see table +SELECT v_ab.a FROM v_ab; + a +---- + 10 +(1 row) + +CREATE SCHEMA v_ab; +CREATE VARIABLE v_ab.a AS integer; +-- we should see table +SELECT v_ab.a FROM v_ab; + a +---- + 10 +(1 row) + +DROP VARIABLE v_ab; +DROP TABLE v_ab; +DROP TYPE ab; +CREATE TYPE t_am_type AS (b int); +CREATE SCHEMA xxx_am; +SET search_path TO public; +CREATE VARIABLE xxx_am AS t_am_type; +LET xxx_am = ROW(10); +-- should be ok +SELECT xxx_am; + xxx_am +-------- + (10) +(1 row) + +CREATE VARIABLE xxx_am.b AS int; +LET :"DBNAME".xxx_am.b = 20; +-- should be still ok +SELECT xxx_am; + xxx_am +-------- + (10) +(1 row) + +-- should fail, the reference should be ambiguous +SELECT xxx_am.b; +ERROR: session variable reference "xxx_am.b" is ambiguous +LINE 1: SELECT xxx_am.b; + ^ +-- enhanced references should be ok +SELECT public.xxx_am.b; + b +---- + 10 +(1 row) + +SELECT :"DBNAME".xxx_am.b; + b +---- + 20 +(1 row) + +CREATE TABLE xxx_am(b int); +INSERT INTO xxx_am VALUES(10); +-- we should see table +SELECT xxx_am.b FROM xxx_am; + b +---- + 10 +(1 row) + +SELECT x.b FROM xxx_am x; + b +---- + 10 +(1 row) + +DROP TABLE xxx_am; +DROP VARIABLE public.xxx_am; +DROP VARIABLE xxx_am.b; +DROP SCHEMA xxx_am; +CREATE SCHEMA :"DBNAME"; +CREATE VARIABLE :"DBNAME".:"DBNAME".:"DBNAME" AS t_am_type; +CREATE VARIABLE :"DBNAME".:"DBNAME".b AS int; +SET search_path TO :"DBNAME"; +-- should be ambiguous +SELECT :"DBNAME".b; +ERROR: session variable reference "regression.b" is ambiguous +LINE 1: SELECT "regression".b; + ^ +-- should be ambiguous too +SELECT :"DBNAME".:"DBNAME".b; +ERROR: session variable reference "regression.regression.b" is ambiguous +LINE 1: SELECT "regression"."regression".b; + ^ +CREATE TABLE :"DBNAME"(b int); +-- should be ok +SELECT :"DBNAME".b FROM :"DBNAME"; + b +--- +(0 rows) + +DROP TABLE :"DBNAME"; +DROP VARIABLE :"DBNAME".:"DBNAME".b; +DROP VARIABLE :"DBNAME".:"DBNAME".:"DBNAME"; +DROP SCHEMA :"DBNAME"; +RESET search_path; diff --git a/src/test/regress/sql/session_variables.sql b/src/test/regress/sql/session_variables.sql index 42dfb95a022..d5bb5dc83be 100644 --- a/src/test/regress/sql/session_variables.sql +++ b/src/test/regress/sql/session_variables.sql @@ -59,3 +59,640 @@ DROP VARIABLE svartest.var1; DROP SCHEMA svartest; DROP ROLE regress_variable_owner; + +-- check access rights +CREATE ROLE regress_noowner; + +CREATE VARIABLE var1 AS int; + +CREATE OR REPLACE FUNCTION sqlfx(int) +RETURNS int AS $$ SELECT $1 + var1 $$ LANGUAGE sql; + +CREATE OR REPLACE FUNCTION sqlfx_sd(int) +RETURNS int AS $$ SELECT $1 + var1 $$ LANGUAGE sql SECURITY DEFINER; + +CREATE OR REPLACE FUNCTION plpgsqlfx(int) +RETURNS int AS $$ BEGIN RETURN $1 + var1; END $$ LANGUAGE plpgsql; + +CREATE OR REPLACE FUNCTION plpgsqlfx_sd(int) +RETURNS int AS $$ BEGIN RETURN $1 + var1; END $$ LANGUAGE plpgsql SECURITY DEFINER; + +LET var1 = 10; +-- should be ok +SELECT var1; +SELECT sqlfx(20); +SELECT sqlfx_sd(20); +SELECT plpgsqlfx(20); +SELECT plpgsqlfx_sd(20); + +-- should fail +SET ROLE TO regress_noowner; + +SELECT var1; +SELECT sqlfx(20); +SELECT plpgsqlfx(20); + +-- should be ok +SELECT sqlfx_sd(20); +SELECT plpgsqlfx_sd(20); + +SET ROLE TO DEFAULT; +GRANT SELECT ON VARIABLE var1 TO regress_noowner; + +-- should be ok +SET ROLE TO regress_noowner; + +SELECT var1; +SELECT sqlfx(20); +SELECT plpgsqlfx(20); + +SET ROLE TO DEFAULT; +DROP VARIABLE var1; +DROP FUNCTION sqlfx(int); +DROP FUNCTION plpgsqlfx(int); +DROP FUNCTION sqlfx_sd(int); +DROP FUNCTION plpgsqlfx_sd(int); + +DROP ROLE regress_noowner; + +-- use variables inside views +CREATE VARIABLE var1 AS numeric; + +-- use variables in views +CREATE VIEW test_view AS SELECT COALESCE(var1 + v, 0) AS result FROM generate_series(1,2) g(v); +SELECT * FROM test_view; +LET var1 = 3.14; +SELECT * FROM test_view; + +-- start a new session +\c + +SELECT * FROM test_view; +LET var1 = 3.14; +SELECT * FROM test_view; + +-- should fail, dependency +DROP VARIABLE var1; + +-- should be ok +DROP VARIABLE var1 CASCADE; + +CREATE VARIABLE var1 text; +CREATE VARIABLE var2 text; + +-- use variables in SQL functions +CREATE OR REPLACE FUNCTION sqlfx1(varchar) +RETURNS varchar AS $$ SELECT var1 || ', ' || $1 $$ LANGUAGE sql; + +CREATE OR REPLACE FUNCTION sqlfx2( varchar) +RETURNS varchar AS $$ SELECT var2 || ', ' || $1 $$ LANGUAGE sql; + +LET var1 = 'str1'; +LET var2 = 'str2'; + +SELECT sqlfx1(sqlfx2('Hello')); + +-- inlining is blocked +EXPLAIN (COSTS OFF, VERBOSE) SELECT sqlfx1(sqlfx2('Hello')); + +DROP FUNCTION sqlfx1(varchar); +DROP FUNCTION sqlfx2(varchar); +DROP VARIABLE var1; +DROP VARIABLE var2; + +-- access from cached plans should work +CREATE VARIABLE var1 AS numeric; + +CREATE OR REPLACE FUNCTION plpgsqlfx() +RETURNS numeric AS $$ BEGIN RETURN var1; END $$ LANGUAGE plpgsql; + +set plan_cache_mode TO force_generic_plan; + +LET var1 = 3.14; +SELECT plpgsqlfx(); +LET var1 = 3.14 * 2; +SELECT plpgsqlfx(); + +DROP VARIABLE var1; + +-- dependency (plan invalidation) should work +CREATE VARIABLE var1 AS numeric; + +LET var1 = 3.14 * 3; +SELECT plpgsqlfx(); +LET var1 = 3.14 * 4; +SELECT plpgsqlfx(); + +DROP VARIABLE var1; +DROP FUNCTION plpgsqlfx(); + +set plan_cache_mode TO DEFAULT; + +-- usage LET statement in plpgsql should work +CREATE VARIABLE var1 int; +CREATE VARIABLE var2 numeric[]; + +DO $$ +BEGIN + LET var2 = '{}'::int[]; + FOR i IN 1..10 + LOOP + LET var1 = i; + LET var2[var1] = i; + END LOOP; + RAISE NOTICE 'result array: %', var2; +END; +$$; + +DROP VARIABLE var1; +DROP VARIABLE var2; + +-- CALL statement is not supported yet +-- requires direct access to session variable from expression executor +CREATE VARIABLE v int; + +CREATE PROCEDURE p(arg int) AS $$ BEGIN RAISE NOTICE '%', arg; END $$ LANGUAGE plpgsql; + +-- should not crash (but is not supported yet) +CALL p(v); + +DO $$ BEGIN CALL p(v); END $$; + +DROP PROCEDURE p(int); +DROP VARIABLE v; + +-- EXECUTE statement is not supported yet +-- requires direct access to session variable from expression executor +CREATE VARIABLE v int; +LET v = 20; +PREPARE ptest(int) AS SELECT $1; + +-- should fail +EXECUTE ptest(v); + +DEALLOCATE ptest; +DROP VARIABLE v; + +-- test search path +CREATE SCHEMA svartest; +CREATE VARIABLE svartest.var1 AS numeric; + +-- should fail +LET var1 = pi(); +SELECT var1; + +-- should be ok +LET svartest.var1 = pi(); +SELECT svartest.var1; + +SET search_path TO svartest; + +-- should be ok +LET var1 = pi() + 10; +SELECT var1; + +RESET search_path; +DROP SCHEMA svartest CASCADE; + +CREATE VARIABLE var1 AS text; + +-- variables can be updated under RO transaction +BEGIN; +SET TRANSACTION READ ONLY; +LET var1 = 'hello'; +COMMIT; + +SELECT var1; + +DROP VARIABLE var1; + +-- test of domains +CREATE DOMAIN int_domain AS int NOT NULL CHECK (VALUE > 100); +CREATE VARIABLE var1 AS int_domain; + +-- should fail +SELECT var1; + +-- should be ok +LET var1 = 1000; +SELECT var1; + +-- should fail +LET var1 = 10; + +-- should fail +LET var1 = NULL; + +-- note - domain defaults are not supported yet (like PLpgSQL) + +DROP VARIABLE var1; +DROP DOMAIN int_domain; + +-- the expression should remain "unknown" +CREATE VARIABLE var1 AS int4multirange[]; +-- should be ok +LET var1 = NULL; +LET var1 = '{"{[2,8),[11,14)}","{[5,8),[12,14)}"}'; +LET var1[2] = '{[5,8),[12,100)}'; +SELECT var1; + +--It should work in plpgsql too +DO $$ +BEGIN + LET var1 = NULL; + LET var1 = '{"{[2,8),[11,14)}","{[5,8),[12,14)}"}'; + LET var1[2] = '{[5,8),[12,100)}'; + + RAISE NOTICE '%', var1; +END; +$$; + +DROP VARIABLE var1; + +CREATE SCHEMA svartest CREATE VARIABLE var1 AS int CREATE TABLE foo(a int); +LET svartest.var1 = 100; +SELECT svartest.var1; + +SET search_path to public, svartest; + +SELECT var1; + +DROP SCHEMA svartest CASCADE; + +CREATE VARIABLE var1 AS int; +CREATE VARIABLE var2 AS int[]; + +LET var1 = 2; +LET var2 = '{}'::int[]; + +LET var2[var1] = 0; + +SELECT var2; + +DROP VARIABLE var1, var2; + +CREATE VARIABLE var1 AS int; +CREATE VARIABLE var2 AS int[]; + +LET var1 = 2; +LET var2 = '{}'::int[]; + +SELECT var2; + +DROP VARIABLE var1, var2; + +-- the LET statement should be disallowed in CTE +CREATE VARIABLE var1 AS int; +WITH x AS (LET var1 = 100) SELECT * FROM x; + +-- should be ok +LET var1 = generate_series(1, 1); + +-- should fail +LET var1 = generate_series(1, 2); +LET var1 = generate_series(1, 0); + +DROP VARIABLE var1; + +-- composite variables +CREATE TYPE sv_xyz AS (x int, y int, z numeric(10,2)); + +CREATE VARIABLE v1 AS sv_xyz; +CREATE VARIABLE v2 AS sv_xyz; + +LET v1 = (1, 2, 3.14); +LET v2 = (10, 20, 3.14 * 10); + +-- should work too - there are prepared casts +LET v1 = (1, 2, 3); + +SELECT v1; +SELECT v2; +SELECT (v1).*; +SELECT (v2).*; + +SELECT v1.x + v1.z; +SELECT v2.x + v2.z; + +-- access to composite fields should be safe too +CREATE ROLE regress_var_test_role; + +SET ROLE TO regress_var_test_role; + +-- should fail +SELECT v2.x; + +SET ROLE TO DEFAULT; + +DROP VARIABLE v1; +DROP VARIABLE v2; + +DROP ROLE regress_var_test_role; + +CREATE TYPE t1 AS (a int, b numeric, c text); + +CREATE VARIABLE v1 AS t1; +LET v1 = (1, pi(), 'hello'); +SELECT v1; +LET v1.b = 10.2222; +SELECT v1; + +-- should fail, attribute doesn't exist +LET v1.x = 10; + +-- should fail, don't allow multi column query +LET v1 = (NULL::t1).*; + +-- allow DROP or ADD ATTRIBUTE on composite types +-- should be ok +ALTER TYPE t1 DROP ATTRIBUTE c; +SELECT v1; + +-- should be ok +ALTER TYPE t1 ADD ATTRIBUTE c int; +SELECT v1; + +LET v1 = (10, 10.3, 20); +SELECT v1; + +-- should be ok +ALTER TYPE t1 DROP ATTRIBUTE b; +SELECT v1; + +-- should fail, disallow data type change +ALTER TYPE t1 ALTER ATTRIBUTE c TYPE int; + +DROP VARIABLE v1; +DROP TYPE t1; + +-- the table type can be used as composite type too +CREATE TABLE svar_test(a int, b numeric, c date); +CREATE VARIABLE var1 AS svar_test; + +LET var1 = (10, pi(), '2023-05-26'); +SELECT var1; + +-- should fail due dependency +ALTER TABLE svar_test ALTER COLUMN a TYPE text; + +-- should fail +DROP TABLE svar_test; + +DROP VARIABLE var1; +DROP TABLE svar_test; + +-- arrays are supported +CREATE VARIABLE var1 AS numeric[]; +LET var1 = ARRAY[1.1,2.1]; +LET var1[1] = 10.1; +SELECT var1; + +-- LET target doesn't allow srf, should fail +LET var1[generate_series(1,3)] = 100; + +DROP VARIABLE var1; + +-- arrays inside composite +CREATE TYPE t1 AS (a numeric, b numeric[]); +CREATE VARIABLE var1 AS t1; +LET var1 = (10.1, ARRAY[0.0, 0.0]); +LET var1.a = 10.2; +SELECT var1; +LET var1.b[1] = 10.3; +SELECT var1; + +DROP VARIABLE var1; +DROP TYPE t1; + +-- Encourage use of parallel plans +SET parallel_setup_cost = 0; +SET parallel_tuple_cost = 0; +SET min_parallel_table_scan_size = 0; +SET max_parallel_workers_per_gather = 2; + +-- test on query with workers +CREATE TABLE svar_test(a int); +INSERT INTO svar_test SELECT * FROM generate_series(1,1000); +ANALYZE svar_test; +CREATE VARIABLE zero int; +LET zero = 0; + +-- result should be 100 +SELECT count(*) FROM svar_test WHERE a%10 = zero; + +-- parallel execution is not supported yet +EXPLAIN (COSTS OFF) SELECT count(*) FROM svar_test WHERE a%10 = zero; + +LET zero = (SELECT count(*) FROM svar_test); + +-- result should be 1000 +SELECT zero; + +DROP VARIABLE zero; +DROP TABLE svar_test; + +RESET parallel_setup_cost; +RESET parallel_tuple_cost; +RESET min_parallel_table_scan_size; +RESET max_parallel_workers_per_gather; + +-- the result of view should be same in parallel mode too +CREATE VARIABLE var1 AS int; +LET var1 = 10; + +CREATE VIEW var1view AS SELECT COALESCE(var1, 0) AS result; + +SELECT * FROM var1view; + +SET debug_parallel_query TO on; + +SELECT * FROM var1view; + +SET debug_parallel_query TO off; + +DROP VIEW var1view; +DROP VARIABLE var1; + +CREATE VARIABLE varid int; +CREATE TABLE svar_test(id int, v int); + +LET varid = 1; +INSERT INTO svar_test VALUES(varid, 100); +SELECT * FROM svar_test; +UPDATE svar_test SET v = 200 WHERE id = varid; +SELECT * FROM svar_test; +DELETE FROM svar_test WHERE id = varid; +SELECT * FROM svar_test; + +DROP TABLE svar_test; +DROP VARIABLE varid; + + +-- visibility check +-- variables should be shadowed always +CREATE VARIABLE var1 AS text; +SELECT var1.relname FROM pg_class var1 WHERE var1.relname = 'pg_class'; + +DROP VARIABLE var1; + +CREATE TABLE xxtab(avar int); + +INSERT INTO xxtab VALUES(333); + +CREATE TYPE xxtype AS (avar int); + +CREATE VARIABLE xxtab AS xxtype; + +INSERT INTO xxtab VALUES(10); + +-- it is ambiguous, but columns are preferred +SELECT xxtab.avar FROM xxtab; + +-- should be ok +SELECT avar FROM xxtab; + +CREATE VARIABLE public.avar AS int; + +-- should be ok, see the table +SELECT avar FROM xxtab; + +-- should be ok +SELECT public.avar FROM xxtab; + +DROP VARIABLE xxtab; + +SELECT xxtab.avar FROM xxtab; + +DROP VARIABLE public.avar; + +DROP TYPE xxtype; + +DROP TABLE xxtab; + +-- The variable can be shadowed by table or by alias +CREATE TYPE public.svar_type AS (a int, b int, c int); +CREATE VARIABLE public.svar AS public.svar_type; + +CREATE TABLE public.svar(a int, b int); + +INSERT INTO public.svar VALUES(10, 20); + +LET public.svar = (100, 200, 300); + +-- should be ok +-- show table +SELECT * FROM public.svar; +SELECT svar.a FROM public.svar; +SELECT svar.* FROM public.svar; + +-- show variable +SELECT public.svar; +SELECT public.svar.c; +SELECT (public.svar).*; + +-- the variable is shadowed, raise error +SELECT public.svar.c FROM public.svar; + +-- can be fixed by alias +SELECT public.svar.c FROM public.svar x; + +SELECT svar.a FROM public.svar; +SELECT svar.* FROM public.svar; + +-- show variable +SELECT public.svar; +SELECT public.svar.c; +SELECT (public.svar).*; + +-- the variable is shadowed, raise error +SELECT public.svar.c FROM public.svar; + +-- can be fixed by alias +SELECT public.svar.c FROM public.svar x; + +DROP VARIABLE public.svar; +DROP TABLE public.svar; +DROP TYPE public.svar_type; + +CREATE TYPE ab AS (a integer, b integer); + +CREATE VARIABLE v_ab AS ab; + +CREATE TABLE v_ab (a integer, b integer); +INSERT INTO v_ab VALUES(10,20); + +-- we should see table +SELECT v_ab.a FROM v_ab; + +CREATE SCHEMA v_ab; + +CREATE VARIABLE v_ab.a AS integer; + +-- we should see table +SELECT v_ab.a FROM v_ab; + +DROP VARIABLE v_ab; +DROP TABLE v_ab; +DROP TYPE ab; + +CREATE TYPE t_am_type AS (b int); +CREATE SCHEMA xxx_am; + +SET search_path TO public; + +CREATE VARIABLE xxx_am AS t_am_type; +LET xxx_am = ROW(10); + +-- should be ok +SELECT xxx_am; + +CREATE VARIABLE xxx_am.b AS int; +LET :"DBNAME".xxx_am.b = 20; + +-- should be still ok +SELECT xxx_am; + +-- should fail, the reference should be ambiguous +SELECT xxx_am.b; + +-- enhanced references should be ok +SELECT public.xxx_am.b; +SELECT :"DBNAME".xxx_am.b; + +CREATE TABLE xxx_am(b int); +INSERT INTO xxx_am VALUES(10); + +-- we should see table +SELECT xxx_am.b FROM xxx_am; +SELECT x.b FROM xxx_am x; + +DROP TABLE xxx_am; +DROP VARIABLE public.xxx_am; +DROP VARIABLE xxx_am.b; +DROP SCHEMA xxx_am; + +CREATE SCHEMA :"DBNAME"; + +CREATE VARIABLE :"DBNAME".:"DBNAME".:"DBNAME" AS t_am_type; +CREATE VARIABLE :"DBNAME".:"DBNAME".b AS int; + +SET search_path TO :"DBNAME"; + +-- should be ambiguous +SELECT :"DBNAME".b; + +-- should be ambiguous too +SELECT :"DBNAME".:"DBNAME".b; + +CREATE TABLE :"DBNAME"(b int); + +-- should be ok +SELECT :"DBNAME".b FROM :"DBNAME"; + +DROP TABLE :"DBNAME"; + +DROP VARIABLE :"DBNAME".:"DBNAME".b; +DROP VARIABLE :"DBNAME".:"DBNAME".:"DBNAME"; +DROP SCHEMA :"DBNAME"; + +RESET search_path; diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 20c3b77a3d7..9cd6c332a75 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -1496,6 +1496,7 @@ LargeObjectDesc Latch LauncherLastStartTimesEntry LerpFunc +LetStmt LexDescr LexemeEntry LexemeHashKey @@ -2599,6 +2600,7 @@ SerializedTransactionState Session SessionBackupState SessionEndType +SessionVariableValue SetConstraintState SetConstraintStateData SetConstraintTriggerData @@ -2789,6 +2791,9 @@ SupportRequestRows SupportRequestSelectivity SupportRequestSimplify SupportRequestWFuncMonotonic +SVariable +SVariableData +SVariableState Syn SyncOps SyncRepConfigData -- 2.46.0