diff --git a/src/backend/distributed/planner/multi_master_planner.c b/src/backend/distributed/planner/multi_master_planner.c
index 2558267d4..7d903ac66 100644
--- a/src/backend/distributed/planner/multi_master_planner.c
+++ b/src/backend/distributed/planner/multi_master_planner.c
@@ -134,6 +134,7 @@ BuildAggregatePlan(Query *masterQuery, Plan *subPlan)
 	Assert(masterQuery->hasAggs || masterQuery->groupClause);
 
 	aggregateTargetList = masterQuery->targetList;
+	memset(&aggregateCosts, 0, sizeof(AggClauseCosts));
 	count_agg_clauses(NULL, (Node *) aggregateTargetList, &aggregateCosts);
 
 	/*