From f5b72b015066053ed3396f0ea010ae470911f3b6 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 11 May 2025 13:38:31 -0400 Subject: [PATCH v1 09/11] Avoid per-relation leakage in autovacuum. PgStat_StatTabEntry and AutoVacOpts structs were leaked until the end of the autovacuum worker's run, which is bad news if there are a lot of relations in the database. Note: pfree'ing the PgStat_StatTabEntry structs here seems a bit risky, because pgstat_fetch_stat_tabentry_ext does not guarantee anything about whether its result is long-lived. That API could use a re-think. Also, free a couple of structures retail when USE_VALGRIND. This doesn't have any effect on the process's total memory consumption, but it does reduce noise in valgrind leakage reports. Author: Tom Lane Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us --- src/backend/postmaster/autovacuum.c | 47 ++++++++++++++++++++++++----- 1 file changed, 40 insertions(+), 7 deletions(-) diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 4d4a1a3197e..ebe8af1056d 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -2077,6 +2077,12 @@ do_autovacuum(void) } } } + + /* Release stuff to avoid per-relation leakage */ + if (relopts) + pfree(relopts); + if (tabentry) + pfree(tabentry); } table_endscan(relScan); @@ -2093,7 +2099,8 @@ do_autovacuum(void) Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple); PgStat_StatTabEntry *tabentry; Oid relid; - AutoVacOpts *relopts = NULL; + AutoVacOpts *relopts; + bool free_relopts = false; bool dovacuum; bool doanalyze; bool wraparound; @@ -2111,7 +2118,9 @@ do_autovacuum(void) * main rel */ relopts = extract_autovac_opts(tuple, pg_class_desc); - if (relopts == NULL) + if (relopts) + free_relopts = true; + else { av_relation *hentry; bool found; @@ -2132,6 +2141,12 @@ do_autovacuum(void) /* ignore analyze for toast tables */ if (dovacuum) table_oids = lappend_oid(table_oids, relid); + + /* Release stuff to avoid leakage */ + if (free_relopts) + pfree(relopts); + if (tabentry) + pfree(tabentry); } table_endscan(relScan); @@ -2503,6 +2518,8 @@ deleted: pg_atomic_test_set_flag(&MyWorkerInfo->wi_dobalance); } + list_free(table_oids); + /* * Perform additional work items, as requested by backends. */ @@ -2545,8 +2562,15 @@ deleted: /* * We leak table_toast_map here (among other things), but since we're - * going away soon, it's not a problem. + * going away soon, it's not a problem normally. But when using Valgrind, + * release some stuff to reduce complaints about leaked storage. */ +#ifdef USE_VALGRIND + hash_destroy(table_toast_map); + FreeTupleDesc(pg_class_desc); + if (bstrategy) + pfree(bstrategy); +#endif /* * Update pg_database.datfrozenxid, and truncate pg_xact if possible. We @@ -2684,8 +2708,8 @@ deleted2: /* * extract_autovac_opts * - * Given a relation's pg_class tuple, return the AutoVacOpts portion of - * reloptions, if set; otherwise, return NULL. + * Given a relation's pg_class tuple, return a palloc'd copy of the + * AutoVacOpts portion of reloptions, if set; otherwise, return NULL. * * Note: callers do not have a relation lock on the table at this point, * so the table could have been dropped, and its catalog rows gone, after @@ -2734,6 +2758,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map, autovac_table *tab = NULL; bool wraparound; AutoVacOpts *avopts; + bool free_avopts = false; /* fetch the relation's relcache entry */ classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid)); @@ -2746,8 +2771,10 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map, * main table reloptions if the toast table itself doesn't have. */ avopts = extract_autovac_opts(classTup, pg_class_desc); - if (classForm->relkind == RELKIND_TOASTVALUE && - avopts == NULL && table_toast_map != NULL) + if (avopts) + free_avopts = true; + else if (classForm->relkind == RELKIND_TOASTVALUE && + table_toast_map != NULL) { av_relation *hentry; bool found; @@ -2856,6 +2883,8 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map, avopts->vacuum_cost_delay >= 0)); } + if (free_avopts) + pfree(avopts); heap_freetuple(classTup); return tab; } @@ -2887,6 +2916,10 @@ recheck_relation_needs_vacanalyze(Oid relid, effective_multixact_freeze_max_age, dovacuum, doanalyze, wraparound); + /* Release tabentry to avoid leakage */ + if (tabentry) + pfree(tabentry); + /* ignore ANALYZE for toast tables */ if (classForm->relkind == RELKIND_TOASTVALUE) *doanalyze = false; -- 2.43.5