v2-0001-Fix-memory-leak-in-pgoutput-with-publication-list.patch

From 22795bd2c7a8c7934d4ac77cfe1cd2ef36ae9fd3 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Mon, 2 Dec 2024 09:50:01 +0900
Subject: [PATCH v2 1/2] Fix memory leak in pgoutput with publication list
 cache

Blah.

Analyzed-by: Jeff Davis, Michael Paquier
Author: Alvaro Herrera
Discussion: https://postgr.es/m/Z0khf9EVMVLOc_YY@paquier.xyz
Backpatch-through: 13
---
 src/backend/replication/pgoutput/pgoutput.c | 22 ++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 5e23453f07..41d204ac3b 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -2060,15 +2060,23 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 		char		relkind = get_rel_relkind(relid);
 		List	   *rel_publications = NIL;
 
-		/* Reload publications if needed before use. */
+		/*
+		 * Reload publications if needed before use.  A dedicated memory
+		 * context is used to hold the publication information, so as any
+		 * memory allocated within LoadPublications() is freed.
+		 */
 		if (!publications_valid)
 		{
-			oldctx = MemoryContextSwitchTo(CacheMemoryContext);
-			if (data->publications)
-			{
-				list_free_deep(data->publications);
-				data->publications = NIL;
-			}
+			static MemoryContext pubmemcxt = NULL;
+
+			if (pubmemcxt == NULL)
+				pubmemcxt = AllocSetContextCreate(CacheMemoryContext,
+												  "publication list context",
+												  ALLOCSET_DEFAULT_SIZES);
+			else
+				MemoryContextReset(pubmemcxt);
+			oldctx = MemoryContextSwitchTo(pubmemcxt);
+
 			data->publications = LoadPublications(data->publication_names);
 			MemoryContextSwitchTo(oldctx);
 			publications_valid = true;
-- 
2.45.2