Fix temporary memory leak in system table index scans

petere · petere · commit 1acf10549e64 · 2024-12-03T09:04:20.000+01:00
Commit 811af97 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
@@ -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
