From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 3 Dec 2024 08:04:20 +0000 (+0100)
Subject: Fix temporary memory leak in system table index scans
X-Git-Tag: REL_18_BETA1~1363
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=1acf10549e64c6a52ced570d712fcba1a2f5d1ec;p=postgresql.git

Fix temporary memory leak in system table index scans

Commit 811af9786b introduced palloc() calls into systable_beginscan()
and systable_beginscan_ordered().  But there was no pfree(), as is the
usual style.

It turns out that an ANALYZE of a partitioned table can invoke many
thousand system table index scans, and this memory is not cleaned up
until the end of the command, so this can temporarily leak quite a bit
of memory.  Maybe there are improvements to be made at a higher level
about this, but for now, insert a couple of corresponding pfree()
calls to fix this particular issue.

Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://www.postgresql.org/message-id/Z0XTfIq5xUtbkiIh@pryzbyj2023
---

diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c
index 60c61039d66..4b4ebff6a17 100644
--- a/src/backend/access/index/genam.c
+++ b/src/backend/access/index/genam.c
@@ -449,6 +449,8 @@ systable_beginscan(Relation heapRelation,
 										 snapshot, nkeys, 0);
 		index_rescan(sysscan->iscan, idxkey, nkeys, NULL, 0);
 		sysscan->scan = NULL;
+
+		pfree(idxkey);
 	}
 	else
 	{
@@ -713,6 +715,8 @@ systable_beginscan_ordered(Relation heapRelation,
 	index_rescan(sysscan->iscan, idxkey, nkeys, NULL, 0);
 	sysscan->scan = NULL;
 
+	pfree(idxkey);
+
 	/*
 	 * If CheckXidAlive is set then set a flag to indicate that system table
 	 * scan is in-progress.  See detailed comments in xact.c where these