Errors for CTEs with search clause

Relevant PG commit:
3696a600e2292d43c00949ddf0352e4ebb487e5b

src/backend/distributed/planner/multi_router_planner.c

@@ -158,6 +158,10 @@ static List * ExtractInsertValuesList(Query *query, Var *partitionColumn);
 static DeferredErrorMessage * DeferErrorIfUnsupportedRouterPlannableSelectQuery(
 	Query *query);
 static DeferredErrorMessage * ErrorIfQueryHasUnroutableModifyingCTE(Query *queryTree);
+#if PG_VERSION_NUM >= PG_VERSION_14
+static DeferredErrorMessage * ErrorIfQueryHasCTEWithSearchClause(Query *queryTree);
+static bool ContainsSearchClauseWalker(Node *node);
+#endif
 static bool SelectsFromDistributedTable(List *rangeTableList, Query *query);
 static ShardPlacement * CreateDummyPlacement(bool hasLocalRelation);
 static ShardPlacement * CreateLocalDummyPlacement();
@@ -1070,6 +1074,15 @@ ModifyQuerySupported(Query *queryTree, Query *originalQuery, bool multiShardQuer
 		}
 	}
 
+#if PG_VERSION_NUM >= PG_VERSION_14
+	DeferredErrorMessage *CTEWithSearchClauseError =
+		ErrorIfQueryHasCTEWithSearchClause(originalQuery);
+	if (CTEWithSearchClauseError != NULL)
+	{
+		return CTEWithSearchClauseError;
+	}
+#endif
+
 	return NULL;
 }
 
@@ -3623,6 +3636,15 @@ DeferErrorIfUnsupportedRouterPlannableSelectQuery(Query *query)
 							 NULL, NULL);
 	}
 
+#if PG_VERSION_NUM >= PG_VERSION_14
+	DeferredErrorMessage *CTEWithSearchClauseError =
+		ErrorIfQueryHasCTEWithSearchClause(query);
+	if (CTEWithSearchClauseError != NULL)
+	{
+		return CTEWithSearchClauseError;
+	}
+#endif
+
 	return ErrorIfQueryHasUnroutableModifyingCTE(query);
 }
 
@@ -3756,6 +3778,57 @@ ErrorIfQueryHasUnroutableModifyingCTE(Query *queryTree)
 }
 
 
+#if PG_VERSION_NUM >= PG_VERSION_14
+
+/*
+ * ErrorIfQueryHasCTEWithSearchClause checks if the query contains any common table
+ * expressions with search clause and errors out if it does.
+ */
+static DeferredErrorMessage *
+ErrorIfQueryHasCTEWithSearchClause(Query *queryTree)
+{
+	if (ContainsSearchClauseWalker((Node *) queryTree))
+	{
+		return DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
+							 "CTEs with search clauses are not supported",
+							 NULL, NULL);
+	}
+	return NULL;
+}
+
+
+/*
+ * ContainsSearchClauseWalker walks over the node and finds if there are any
+ * CommonTableExprs with search clause
+ */
+static bool
+ContainsSearchClauseWalker(Node *node)
+{
+	if (node == NULL)
+	{
+		return false;
+	}
+
+	if (IsA(node, CommonTableExpr))
+	{
+		if (((CommonTableExpr *) node)->search_clause != NULL)
+		{
+			return true;
+		}
+	}
+
+	if (IsA(node, Query))
+	{
+		return query_tree_walker((Query *) node, ContainsSearchClauseWalker, NULL, 0);
+	}
+
+	return expression_tree_walker(node, ContainsSearchClauseWalker, NULL);
+}
+
+
+#endif
+
+
 /*
  * get_all_actual_clauses
  *

src/test/regress/expected/pg14.out

@@ -644,5 +644,74 @@ REINDEX TABLE dist_part_table;
 ERROR:  REINDEX TABLE queries on distributed partitioned tables are not supported
 -- but we support REINDEXing partitions
 REINDEX TABLE dist_part_table_1;
+-- test if we error with CTEs with search clauses
+CREATE TABLE graph0(f INT, t INT, label TEXT);
+SELECT create_distributed_table('graph0', 'f');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+INSERT INTO graph0 VALUES (1, 2, 'arc 1 -> 2'),
+    (1, 3, 'arc 1 -> 3'), (2, 3, 'arc 2 -> 3'),
+    (1, 4, 'arc 1 -> 4'), (4, 5, 'arc 4 -> 5');
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph0 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+SELECT * FROM search_graph ORDER BY seq;
+ERROR:  recursive CTEs are not supported in distributed queries
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph0 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+DELETE FROM graph0 WHERE t IN (SELECT t FROM search_graph ORDER BY seq);
+ERROR:  recursive CTEs are not supported in distributed queries
+CREATE TABLE graph1(f INT, t INT, label TEXT);
+SELECT create_reference_table('graph1');
+ create_reference_table
+---------------------------------------------------------------------
+
+(1 row)
+
+INSERT INTO graph1 VALUES (1, 2, 'arc 1 -> 2'),
+    (1, 3, 'arc 1 -> 3'), (2, 3, 'arc 2 -> 3'),
+    (1, 4, 'arc 1 -> 4'), (4, 5, 'arc 4 -> 5');
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph1 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph1 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+SELECT * FROM search_graph ORDER BY seq;
+ERROR:  recursive CTEs are not supported in distributed queries
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph1 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph1 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+DELETE FROM graph1 WHERE t IN (SELECT t FROM search_graph ORDER BY seq);
+ERROR:  recursive CTEs are not supported in distributed queries
+SELECT * FROM (
+    WITH RECURSIVE search_graph(f, t, label) AS (
+        SELECT *
+        FROM graph0 g
+        WHERE f = 1
+        UNION ALL SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t AND g.f = 1
+    ) SEARCH DEPTH FIRST BY f, t SET seq
+    SELECT * FROM search_graph ORDER BY seq
+) as foo;
+ERROR:  recursive CTEs are not supported in distributed queries
 set client_min_messages to error;
 drop schema pg14 cascade;

src/test/regress/sql/pg14.sql

@@ -272,5 +272,70 @@ REINDEX TABLE dist_part_table;
 -- but we support REINDEXing partitions
 REINDEX TABLE dist_part_table_1;
 
+
+-- test if we error with CTEs with search clauses
+CREATE TABLE graph0(f INT, t INT, label TEXT);
+SELECT create_distributed_table('graph0', 'f');
+
+INSERT INTO graph0 VALUES (1, 2, 'arc 1 -> 2'),
+    (1, 3, 'arc 1 -> 3'), (2, 3, 'arc 2 -> 3'),
+    (1, 4, 'arc 1 -> 4'), (4, 5, 'arc 4 -> 5');
+
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph0 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+SELECT * FROM search_graph ORDER BY seq;
+
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph0 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+DELETE FROM graph0 WHERE t IN (SELECT t FROM search_graph ORDER BY seq);
+
+CREATE TABLE graph1(f INT, t INT, label TEXT);
+SELECT create_reference_table('graph1');
+
+INSERT INTO graph1 VALUES (1, 2, 'arc 1 -> 2'),
+    (1, 3, 'arc 1 -> 3'), (2, 3, 'arc 2 -> 3'),
+    (1, 4, 'arc 1 -> 4'), (4, 5, 'arc 4 -> 5');
+
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph1 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph1 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+SELECT * FROM search_graph ORDER BY seq;
+
+WITH RECURSIVE search_graph(f, t, label) AS (
+    SELECT * FROM graph1 g WHERE f = 1
+    UNION ALL
+    SELECT g.*
+        FROM graph1 g, search_graph sg
+        WHERE g.f = sg.t and  g.f = 1
+) SEARCH DEPTH FIRST BY f, t SET seq
+DELETE FROM graph1 WHERE t IN (SELECT t FROM search_graph ORDER BY seq);
+
+
+SELECT * FROM (
+    WITH RECURSIVE search_graph(f, t, label) AS (
+        SELECT *
+        FROM graph0 g
+        WHERE f = 1
+        UNION ALL SELECT g.*
+        FROM graph0 g, search_graph sg
+        WHERE g.f = sg.t AND g.f = 1
+    ) SEARCH DEPTH FIRST BY f, t SET seq
+    SELECT * FROM search_graph ORDER BY seq
+) as foo;
+
 set client_min_messages to error;
 drop schema pg14 cascade;