From efc1b0b978781eebcdf92d1d1a88119c8aa49c0b Mon Sep 17 00:00:00 2001 From: "okbob@github.com" Date: Mon, 24 Nov 2025 20:04:16 +0100 Subject: [PATCH 07/11] DISCARD TEMP --- doc/src/sgml/ref/discard.sgml | 3 ++- src/backend/commands/discard.c | 3 +++ src/backend/commands/session_variable.c | 20 +++++++++++++++++++ src/include/commands/session_variable.h | 2 ++ .../expected/session_variables_ddl.out | 7 +++++++ .../regress/sql/session_variables_ddl.sql | 10 ++++++++++ 6 files changed, 44 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/ref/discard.sgml b/doc/src/sgml/ref/discard.sgml index bf44c523cac..2700f7b7cd0 100644 --- a/doc/src/sgml/ref/discard.sgml +++ b/doc/src/sgml/ref/discard.sgml @@ -70,7 +70,8 @@ DISCARD { ALL | PLANS | SEQUENCES | TEMPORARY | TEMP } TEMPORARY or TEMP - Drops all temporary tables created in the current session. + Drops all temporary tables and temporary session variables created in + the current session. diff --git a/src/backend/commands/discard.c b/src/backend/commands/discard.c index 17d172df076..0a33c949fce 100644 --- a/src/backend/commands/discard.c +++ b/src/backend/commands/discard.c @@ -19,6 +19,7 @@ #include "commands/discard.h" #include "commands/prepare.h" #include "commands/sequence.h" +#include "commands/session_variable.h" #include "storage/lock.h" #include "utils/guc.h" #include "utils/portal.h" @@ -47,6 +48,7 @@ DiscardCommand(DiscardStmt *stmt, bool isTopLevel) case DISCARD_TEMP: ResetTempTableNamespace(); + ResetSessionVariables(); break; default: @@ -76,4 +78,5 @@ DiscardAll(bool isTopLevel) ResetPlanCache(); ResetTempTableNamespace(); ResetSequenceCaches(); + ResetSessionVariables(); } diff --git a/src/backend/commands/session_variable.c b/src/backend/commands/session_variable.c index abcb0bb531a..c75f851bad2 100644 --- a/src/backend/commands/session_variable.c +++ b/src/backend/commands/session_variable.c @@ -411,3 +411,23 @@ ExecuteLetStmt(ParseState *pstate, PopActiveSnapshot(); } + +/* + * Fast drop of the complete content of the session variables hash table, and + * cleanup of any list that wouldn't be relevant anymore. + * This is used by the DISCARD TEMP. + */ +void +ResetSessionVariables(void) +{ + /* destroy hash table and reset related memory context */ + if (sessionvars) + { + hash_destroy(sessionvars); + sessionvars = NULL; + } + + /* release memory allocated by session variables */ + if (SVariableMemoryContext != NULL) + MemoryContextReset(SVariableMemoryContext); +} diff --git a/src/include/commands/session_variable.h b/src/include/commands/session_variable.h index c4b4d9e6832..cc1aa7ce23b 100644 --- a/src/include/commands/session_variable.h +++ b/src/include/commands/session_variable.h @@ -37,4 +37,6 @@ extern void get_session_variable_type_typmod_collid(char *varname, extern void ExecuteLetStmt(ParseState *pstate, LetStmt *stmt, ParamListInfo params, QueryEnvironment *queryEnv, QueryCompletion *qc); +extern void ResetSessionVariables(void); + #endif diff --git a/src/test/regress/expected/session_variables_ddl.out b/src/test/regress/expected/session_variables_ddl.out index 45c2d27ab44..c36febd894e 100644 --- a/src/test/regress/expected/session_variables_ddl.out +++ b/src/test/regress/expected/session_variables_ddl.out @@ -41,3 +41,10 @@ DROP VARIABLE x; SET ROLE TO DEFAULT; DROP ROLE regress_session_variable_test_role_01; DROP ROLE regress_session_variable_test_role_02; +CREATE TEMP VARIABLE x AS int; +-- should fail +CREATE TEMP VARIABLE x AS int; +ERROR: session variable "x" already exists +DISCARD TEMP; +-- should be ok +CREATE TEMP VARIABLE x AS int; diff --git a/src/test/regress/sql/session_variables_ddl.sql b/src/test/regress/sql/session_variables_ddl.sql index 34f34dd898f..7fd739d6677 100644 --- a/src/test/regress/sql/session_variables_ddl.sql +++ b/src/test/regress/sql/session_variables_ddl.sql @@ -54,3 +54,13 @@ DROP VARIABLE x; SET ROLE TO DEFAULT; DROP ROLE regress_session_variable_test_role_01; DROP ROLE regress_session_variable_test_role_02; + +CREATE TEMP VARIABLE x AS int; + +-- should fail +CREATE TEMP VARIABLE x AS int; + +DISCARD TEMP; + +-- should be ok +CREATE TEMP VARIABLE x AS int; -- 2.53.0