postgres.git / summary / log / commit / refs
commit 13d21b48a3a4eef4227339d177a5ce2ed2879447
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri May 23 18:43:44 2025 +0000
First released in: 18.0, 15.14, 16.10, 17.6
Fix per-relation memory 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. It appears okay
so long as autovacuum forces PGSTAT_FETCH_CONSISTENCY_NONE, but
I think that API could use a re-think.
Also ensure that the VacuumRelation structure passed to
vacuum() is in recoverable storage.
Back-patch to v15 where we started to manage table statistics
this way. (The AutoVacOpts leakage is probably older, but
I'm not excited enough to worry about just that part.)
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us
Backpatch-through: 15
src/backend/postmaster/autovacuum.c | 38 +++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index d8876fbcb6c..c511a132263 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2154,6 +2154,12 @@ do_autovacuum(void)
}
}
}
+
+ /* Release stuff to avoid per-relation leakage */
+ if (relopts)
+ pfree(relopts);
+ if (tabentry)
+ pfree(tabentry);
}
table_endscan(relScan);
@@ -2170,7 +2176,8 @@ 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;
@@ -2188,7 +2195,9 @@ 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;
@@ -2209,6 +2218,12 @@ 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);
@@ -2572,6 +2587,8 @@ deleted:
VacuumCostLimit = stdVacuumCostLimit;
}
+ list_free(table_oids);
+
/*
* Perform additional work items, as requested by backends.
*/
@@ -2749,8 +2766,8 @@ 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
@@ -2799,6 +2816,7 @@ 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));
@@ -2811,8 +2829,10 @@ 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;
@@ -2921,6 +2941,8 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
avopts->vacuum_cost_delay >= 0));
}
+ if (free_avopts)
+ pfree(avopts);
heap_freetuple(classTup);
return tab;
}
@@ -2952,6 +2974,10 @@ 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;
[parent: 0e0174b4973a]