pgstat: Create memory contexts below TopMemoryContext

anarazel · anarazel · commit 9d3ebba729eb · 2022-09-17T09:04:23.000-07:00
So far they were created below CacheMemoryContext. However, that's not guaranteed to exist in all situations, leading to memory contexts created as top-level contexts. There isn't actually a good reason anymore to create them below CacheMemoryContext, so just creating them below TopMemoryContext seems the best approach. Reported-by: Reid Thompson <reid.thompson@crunchydata.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Author: "Drouvot, Bertrand" <bdrouvot@amazon.com> Discussion: https://postgr.es/m/b948b729-42fe-f88c-2f4a-0e65d84c049b@amazon.com Backpatch: 15-
diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c
@@ -1069,7 +1069,7 @@ pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid, bool *created
 	if (unlikely(!pgStatPendingContext))
 	{
 		pgStatPendingContext =
-			AllocSetContextCreate(CacheMemoryContext,
+			AllocSetContextCreate(TopMemoryContext,
 								  "PgStat Pending",
 								  ALLOCSET_SMALL_SIZES);
 	}
diff --git a/src/backend/utils/activity/pgstat_shmem.c b/src/backend/utils/activity/pgstat_shmem.c
@@ -992,12 +992,12 @@ pgstat_setup_memcxt(void)
 {
 	if (unlikely(!pgStatSharedRefContext))
 		pgStatSharedRefContext =
-			AllocSetContextCreate(CacheMemoryContext,
+			AllocSetContextCreate(TopMemoryContext,
 								  "PgStat Shared Ref",
 								  ALLOCSET_SMALL_SIZES);
 	if (unlikely(!pgStatEntryRefHashContext))
 		pgStatEntryRefHashContext =
-			AllocSetContextCreate(CacheMemoryContext,
+			AllocSetContextCreate(TopMemoryContext,
 								  "PgStat Shared Ref Hash",
 								  ALLOCSET_SMALL_SIZES);
 }

Original file line number	Diff line number	Diff line change
`@@ -1069,7 +1069,7 @@ pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid, Oid objoid, bool *created`
`1069`	`1069`	`if (unlikely(!pgStatPendingContext))`
`1070`	`1070`	`{`
`1071`	`1071`	`pgStatPendingContext =`
`1072`		`- AllocSetContextCreate(CacheMemoryContext,`
	`1072`	`+ AllocSetContextCreate(TopMemoryContext,`
`1073`	`1073`	`"PgStat Pending",`
`1074`	`1074`	`ALLOCSET_SMALL_SIZES);`
`1075`	`1075`	`}`