From b102c8c4733cf76ff0635dc440ee8dd11487ed95 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 2 Aug 2025 19:44:10 -0400 Subject: [PATCH] Silence complaints about leaks in PlanCacheComputeResultDesc. CompleteCachedPlan intentionally doesn't worry about small leaks from PlanCacheComputeResultDesc. However, Valgrind knows nothing of engineering tradeoffs and complains anyway. Silence it by doing things the hard way if USE_VALGRIND. I don't really love this patch, because it makes the handling of plansource->resultDesc different from the handling of query dependencies and search_path just above, which likewise are willing to accept small leaks into the cached plan's context. However, those cases aren't provoking Valgrind complaints. (Perhaps in a CLOBBER_CACHE_ALWAYS build, they would?) For the moment, this makes the src/pl/plpgsql tests leak-free according to Valgrind. Author: Tom Lane Reviewed-by: Andres Freund Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us --- src/backend/utils/cache/plancache.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c index 0c506d320b1..6661d2c6b73 100644 --- a/src/backend/utils/cache/plancache.c +++ b/src/backend/utils/cache/plancache.c @@ -463,8 +463,7 @@ CompleteCachedPlan(CachedPlanSource *plansource, /* * Save the final parameter types (or other parameter specification data) - * into the source_context, as well as our other parameters. Also save - * the result tuple descriptor. + * into the source_context, as well as our other parameters. */ MemoryContextSwitchTo(source_context); @@ -480,9 +479,25 @@ CompleteCachedPlan(CachedPlanSource *plansource, plansource->parserSetupArg = parserSetupArg; plansource->cursor_options = cursor_options; plansource->fixed_result = fixed_result; - plansource->resultDesc = PlanCacheComputeResultDesc(querytree_list); + /* + * Also save the result tuple descriptor. PlanCacheComputeResultDesc may + * leak some cruft; normally we just accept that to save a copy step, but + * in USE_VALGRIND mode be tidy by running it in the caller's context. + */ +#ifdef USE_VALGRIND + MemoryContextSwitchTo(oldcxt); + plansource->resultDesc = PlanCacheComputeResultDesc(querytree_list); + if (plansource->resultDesc) + { + MemoryContextSwitchTo(source_context); + plansource->resultDesc = CreateTupleDescCopy(plansource->resultDesc); + MemoryContextSwitchTo(oldcxt); + } +#else + plansource->resultDesc = PlanCacheComputeResultDesc(querytree_list); MemoryContextSwitchTo(oldcxt); +#endif plansource->is_complete = true; plansource->is_valid = true; -- 2.47.2