diff --git a/createas.c b/createas.c
index efe777c..31fd06b 100644
--- a/createas.c
+++ b/createas.c
@@ -466,6 +466,13 @@ CreateIvmTriggersOnBaseTables(Query *qry, Oid matviewOid, bool is_create)
 	Index	first_rtindex = is_create ? 1 : PRS2_NEW_VARNO + 1;
 	RangeTblEntry *rte;
 
+	/*
+	 * is_create must be true in pg_ivm because the view definition doesn't
+	 * contain NEW/OLD RTE.
+	 * XXX: This argument should be removed?
+	 */
+	Assert(is_create);
+
 	/* Immediately return if we don't have any base tables. */
 	if (list_length(qry->rtable) < first_rtindex)
 		return;
@@ -1095,6 +1102,13 @@ CreateIndexOnIMMV(Query *query, Relation matviewRel, bool is_create)
 	ListCell   *indexoidscan;
 
 
+	/*
+	 * is_create must be true in pg_ivm because the view definition doesn't
+	 * contain NEW/OLD RTE.
+	 * XXX: This argument should be removed?
+	 */
+	Assert(is_create);
+
 	/*
 	 * For aggregate without GROUP BY, we do not need to create an index
 	 * because the view has only one row.
diff --git a/matview.c b/matview.c
index 6e4208f..ae2b02b 100644
--- a/matview.c
+++ b/matview.c
@@ -447,10 +447,7 @@ ExecRefreshImmv(const RangeVar *relation, bool skipData,
 		pgstat_count_heap_insert(matviewRel, processed);
 
 	if (!skipData && !oldPopulated)
-	{
 		CreateIvmTriggersOnBaseTables(viewQuery, matviewOid, true);
-		CreateIvmTriggersOnBaseTables(dataQuery, matviewOid, false);
-	}
 
 	table_close(matviewRel, NoLock);