From 1ca9a5b8677f41179ccc904414cd3946dc17c663 Mon Sep 17 00:00:00 2001
From: Marco Slot <marco.slot@gmail.com>
Date: Thu, 20 Sep 2018 19:28:37 +0200
Subject: [PATCH] Do not allow unresolved parameters in INSERT...SELECT

---
 src/backend/distributed/planner/distributed_planner.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/backend/distributed/planner/distributed_planner.c b/src/backend/distributed/planner/distributed_planner.c
index 6ef0f5824..a17ef0e42 100644
--- a/src/backend/distributed/planner/distributed_planner.c
+++ b/src/backend/distributed/planner/distributed_planner.c
@@ -595,6 +595,16 @@ CreateDistributedPlan(uint64 planId, Query *originalQuery, Query *query, ParamLi
 
 		if (InsertSelectIntoDistributedTable(originalQuery))
 		{
+			if (hasUnresolvedParams)
+			{
+				/*
+				 * Unresolved parameters can cause performance regressions in
+				 * INSERT...SELECT when the partition column is a parameter
+				 * because we don't perform any additional pruning in the executor.
+				 */
+				return NULL;
+			}
+
 			distributedPlan =
 				CreateInsertSelectPlan(originalQuery, plannerRestrictionContext);
 		}