From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 6 Dec 2017 13:42:50 +0000 (-0500)
Subject: Fix Parallel Append crash.
X-Git-Tag: REL_11_BETA1~1103
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9c64ddd414855fb10e0355e887745270a4464c50;p=thirdparty%2Fpostgresql.git

Fix Parallel Append crash.

Reported by Tom Lane and the buildfarm.

Amul Sul and Amit Khandekar

Discussion: http://postgr.es/m/17868.1512519318@sss.pgh.pa.us
Discussion: http://postgr.es/m/CAJ3gD9cJQ4d-XhmZ6BqM9rMM2KDBfpkdgOAb4+psz56uBuMQ_A@mail.gmail.com
---

diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
index 246a0b2d852..0e9371373c1 100644
--- a/src/backend/executor/nodeAppend.c
+++ b/src/backend/executor/nodeAppend.c
@@ -506,8 +506,16 @@ choose_next_subplan_for_worker(AppendState *node)
 	node->as_whichplan = pstate->pa_next_plan++;
 	if (pstate->pa_next_plan >= node->as_nplans)
 	{
-		Assert(append->first_partial_plan < node->as_nplans);
-		pstate->pa_next_plan = append->first_partial_plan;
+		if (append->first_partial_plan < node->as_nplans)
+			pstate->pa_next_plan = append->first_partial_plan;
+		else
+		{
+			/*
+			 * We have only non-partial plans, and we already chose the last
+			 * one; so arrange for the other workers to immediately bail out.
+			 */
+			pstate->pa_next_plan = INVALID_SUBPLAN_INDEX;
+		}
 	}
 
 	/* If non-partial, immediately mark as finished. */