From bd0ebac86591f21550e0ee140ad26ae9eee34209 Mon Sep 17 00:00:00 2001
From: Marco Slot <marco.slot@gmail.com>
Date: Mon, 29 Jan 2018 16:05:10 +0100
Subject: [PATCH] Skip call to ActiveReadableNodeList when there are no
 subplans

---
 src/backend/distributed/executor/subplan_execution.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/backend/distributed/executor/subplan_execution.c b/src/backend/distributed/executor/subplan_execution.c
index 5a3449dfe..72a5860a5 100644
--- a/src/backend/distributed/executor/subplan_execution.c
+++ b/src/backend/distributed/executor/subplan_execution.c
@@ -34,9 +34,17 @@ ExecuteSubPlans(DistributedPlan *distributedPlan)
 	uint64 planId = distributedPlan->planId;
 	List *subPlanList = distributedPlan->subPlanList;
 	ListCell *subPlanCell = NULL;
-	List *nodeList = ActiveReadableNodeList();
+	List *nodeList = NIL;
 	bool writeLocalFile = false;
 
+	if (subPlanList == NIL)
+	{
+		/* no subplans to execute */
+		return;
+	}
+
+	nodeList = ActiveReadableNodeList();
+
 	foreach(subPlanCell, subPlanList)
 	{
 		DistributedSubPlan *subPlan = (DistributedSubPlan *) lfirst(subPlanCell);