From c8e124f6c6d209e39072e6c2859c476bce8c082e Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 11 May 2025 13:32:17 -0400 Subject: [PATCH v1 08/11] Fix some extremely broken code from 525392d57. This uselessly makes two copies of the plan tree during BuildCachedPlan; there should be only one, and it should be in the stmt_context not plan_context. Also, UpdateCachedPlan has a fragile and undocumented assumption that the length of the stmt_list can't change. (The XXX comments in that function have a very strong whiff of code that wasn't really ready to commit, but this is enough fixing to silence Valgrind's complaints about leaked data in the plan_context.) Author: Tom Lane Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us --- src/backend/utils/cache/plancache.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c index 9bcbc4c3e97..53e3255ad7f 100644 --- a/src/backend/utils/cache/plancache.c +++ b/src/backend/utils/cache/plancache.c @@ -1114,17 +1114,18 @@ BuildCachedPlan(CachedPlanSource *plansource, List *qlist, ALLOCSET_START_SMALL_SIZES); MemoryContextCopyAndSetIdentifier(plan_context, plansource->query_string); - stmt_context = AllocSetContextCreate(CurrentMemoryContext, + stmt_context = AllocSetContextCreate(plan_context, "CachedPlan PlannedStmts", ALLOCSET_START_SMALL_SIZES); MemoryContextCopyAndSetIdentifier(stmt_context, plansource->query_string); - MemoryContextSetParent(stmt_context, plan_context); + /* + * Copy plans into the stmt_context. + */ MemoryContextSwitchTo(stmt_context); plist = copyObject(plist); MemoryContextSwitchTo(plan_context); - plist = list_copy(plist); } else plan_context = CurrentMemoryContext; @@ -1207,8 +1208,6 @@ UpdateCachedPlan(CachedPlanSource *plansource, int query_index, { List *query_list = plansource->query_list, *plan_list; - ListCell *l1, - *l2; CachedPlan *plan = plansource->gplan; MemoryContext oldcxt; @@ -1260,12 +1259,7 @@ UpdateCachedPlan(CachedPlanSource *plansource, int query_index, MemoryContextReset(plan->stmt_context); oldcxt = MemoryContextSwitchTo(plan->stmt_context); - forboth(l1, plan_list, l2, plan->stmt_list) - { - PlannedStmt *plannedstmt = lfirst(l1); - - lfirst(l2) = copyObject(plannedstmt); - } + plan->stmt_list = copyObject(plan_list); MemoryContextSwitchTo(oldcxt); /* -- 2.43.5