diff --git a/src/backend/executor/nodeSort.c b/src/backend/executor/nodeSort.c
index 2398bdabf0d..00d65a53aca 100644
--- a/src/backend/executor/nodeSort.c
+++ b/src/backend/executor/nodeSort.c
@@ -263,10 +263,10 @@ ExecInitSort(Sort *node, EState *estate, int eflags)
 	outerTupDesc = ExecGetResultType(outerPlanState(sortstate));
 
 	/*
-	 * We perform a Datum sort when we're sorting just a single column,
-	 * otherwise we perform a tuple sort.
+	 * We perform a Datum sort when we're sorting just a single column by a
+	 * single key, otherwise we perform a tuple sort.
 	 */
-	if (outerTupDesc->natts == 1)
+	if (outerTupDesc->natts == 1 && node->numCols == 1)
 		sortstate->datumSort = true;
 	else
 		sortstate->datumSort = false;