git.postgresql.org Git - postgresql.git/commitdiff

git projects / postgresql.git / commitdiff

Fix per-relation memory leakage in autovacuum.

2025年5月23日 18:43:44 +0000 (14:43 -0400)

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 patch | blob | blame | history

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c

index d8876fbcb6c54e1d77ae5b41af266f4127201250..c511a1322636c2f0d4efaeedcb4ac6c32f15301d 100644 (file)

--- 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;

This is the main PostgreSQL git repository.

RSS Atom