v2_PG15-0001-Fix-memory-leak-in-pgoutput-relation-attribu.patch

From 8ebf0403ea4f972b8cc3e58fc153e38f0e1abc38 Mon Sep 17 00:00:00 2001
From: Vignesh <vignesh21@gmail.com>
Date: Thu, 26 Dec 2024 12:05:33 +0530
Subject: [PATCH v2_PG15] Fix memory leak in pgoutput relation attribute map

The pgoutput module caches relation attribute map only when validating the
RelationSyncEntry.  However, this was not getting freed incase of SQL functions
like pg_logical_slot_{get,peek}_changes() which would bloat its cache memory usage.
Every pg_logical_slot_{get,peek}_changes() call for changes on partition table
creates more bloat. To address this, this relation attribute map is allocated in
the plugin's cachectx which will be freed while the context is freed at
the end of pg_logical_slot_{get,peek}_changes() execution.
---
 src/backend/replication/pgoutput/pgoutput.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index e178bd77ab..64f62de635 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1139,8 +1139,8 @@ init_tuple_slot(PGOutputData *data, Relation relation,
 		TupleDesc	indesc = RelationGetDescr(relation);
 		TupleDesc	outdesc = RelationGetDescr(ancestor);
 
-		/* Map must live as long as the session does. */
-		oldctx = MemoryContextSwitchTo(CacheMemoryContext);
+		/* Map must live as long as the logical decoding context. */
+		oldctx = MemoryContextSwitchTo(data->cachectx);
 
 		entry->attrmap = build_attrmap_by_name_if_req(indesc, outdesc);
 
-- 
2.43.0