we should consider all kinds of tables as colocated if their relation ids are same

src/backend/distributed/planner/relation_restriction_equivalence.c

@@ -171,6 +171,7 @@ static bool FindQueryContainingRTEIdentityInternal(Node *node,
 
 static int ParentCountPriorToAppendRel(List *appendRelList, AppendRelInfo *appendRelInfo);
 
+static bool AllRelationsSame(List *relationList);
 
 /*
  * AllDistributionKeysInQueryAreEqual returns true if either
@@ -1960,6 +1961,31 @@ AllDistributedRelationsInRTEListColocated(List *rangeTableEntryList)
 }
 
 
+/*
+ * AllRelationsSame determines whether all of the relations are the same.
+ */
+static bool
+AllRelationsSame(List *relationList)
+{
+	if (relationList == NULL || list_length(relationList) == 0)
+	{
+		return true;
+	}
+
+	Oid firstRelationId = linitial_oid(relationList);
+	Oid relationId = InvalidOid;
+	foreach_oid(relationId, relationList)
+	{
+		if (relationId != firstRelationId)
+		{
+			return false;
+		}
+	}
+
+	return true;
+}
+
+
 /*
  * AllDistributedRelationsInListColocated determines whether all of the
  * distributed relations in the given list are co-located.
@@ -1967,6 +1993,11 @@ AllDistributedRelationsInRTEListColocated(List *rangeTableEntryList)
 bool
 AllDistributedRelationsInListColocated(List *relationList)
 {
+	if (AllRelationsSame(relationList))
+	{
+		return true;
+	}
+
 	int initialColocationId = INVALID_COLOCATION_ID;
 	Oid relationId = InvalidOid;