Invalidate caches after cranking up a parallel worker transaction.

robertmhaas · robertmhaas · commit 14129d1c9e2d · 2015-10-16T11:33:28.000-04:00
Starting a parallel worker transaction changes our notion of which XIDs are in-progress or committed, and our notion of the current command counter ID. Therefore, our view of these caches prior to starting this transaction may no longer valid. Defend against that by clearing them. This fixes a bug in commit 924bcf4.
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
@@ -28,6 +28,7 @@
 #include "tcop/tcopprot.h"
 #include "utils/combocid.h"
 #include "utils/guc.h"
+#include "utils/inval.h"
 #include "utils/memutils.h"
 #include "utils/resowner.h"
 #include "utils/snapmgr.h"
@@ -928,6 +929,12 @@ ParallelWorkerMain(Datum main_arg)
 	Assert(asnapspace != NULL);
 	PushActiveSnapshot(RestoreSnapshot(asnapspace));
 
+	/*
+	 * We've changed which tuples we can see, and must therefore invalidate
+	 * system caches.
+	 */
+	InvalidateSystemCaches();
+
 	/* Restore user ID and security context. */
 	SetUserIdAndSecContext(fps->current_user_id, fps->sec_context);
 
