From 0b392314315a55aa201f53b2ba71986be91ebc69 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 27 Dec 2009 19:40:07 +0000
Subject: [PATCH] Avoid memory leak if pgstat_vacuum_stat is interrupted
partway through. The temporary hash tables made by pgstat_collect_oids should
be allocated in a short-term memory context, which is not the default
behavior of hash_create. Noted while looking through hash_create calls in
connection with Robert Haas' recent complaint.
This is a pre-existing bug, but it doesn't seem important enough to
back-patch. The hash table is not so large that it would matter unless this
happened many times within a session, which seems quite unlikely.
---
src/backend/postmaster/pgstat.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 4fa2d9fd637..ab88a59eea4 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -13,7 +13,7 @@
*
* Copyright (c) 2001-2009, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.193 2009/11/28 23:38:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.194 2009/12/27 19:40:07 tgl Exp $
* ----------
*/
#include "postgres.h"
@@ -1033,7 +1033,8 @@ pgstat_vacuum_stat(void)
*
* Collect the OIDs of all objects listed in the specified system catalog
* into a temporary hash table. Caller should hash_destroy the result
- * when done with it.
+ * when done with it. (However, we make the table in CurrentMemoryContext
+ * so that it will be freed properly in event of an error.)
* ----------
*/
static HTAB *
@@ -1049,10 +1050,11 @@ pgstat_collect_oids(Oid catalogid)
hash_ctl.keysize = sizeof(Oid);
hash_ctl.entrysize = sizeof(Oid);
hash_ctl.hash = oid_hash;
+ hash_ctl.hcxt = CurrentMemoryContext;
htab = hash_create("Temporary table of OIDs",
PGSTAT_TAB_HASH_SIZE,
&hash_ctl,
- HASH_ELEM | HASH_FUNCTION);
+ HASH_ELEM | HASH_FUNCTION | HASH_CONTEXT);
rel = heap_open(catalogid, AccessShareLock);
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
--
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