bufmgr: Return early in ScheduleBufferTagForWriteback() if fsync=off

anarazel · anarazel · commit 488f826c729b · 2024-10-08T11:37:45.000-04:00
As pg_flush_data() doesn't do anything with fsync disabled, there's no point in tracking the buffer for writeback. Arguably the better fix would be to change pg_flush_data() to flush data even with fsync off, but that's a behavioral change, whereas this is just a small optimization. Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-by: Noah Misch <noah@leadboat.com> Discussion: https://postgr.es/m/1f6b50a7-38ef-4d87-8246-786d39f46ab9@iki.fi
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
@@ -5899,7 +5899,12 @@ ScheduleBufferTagForWriteback(WritebackContext *wb_context, IOContext io_context
 {
 	PendingWriteback *pending;
 
-	if (io_direct_flags & IO_DIRECT_DATA)
+	/*
+	 * As pg_flush_data() doesn't do anything with fsync disabled, there's no
+	 * point in tracking in that case.
+	 */
+	if (io_direct_flags & IO_DIRECT_DATA ||
+		!enableFsync)
 		return;
 
 	/*
