CREATE FOREIGN TABLE LIKE.

src/backend/parser/parse_utilcmd.c

@@ -396,13 +396,19 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 													 likeDistributedBy, bQuiet);
 	}
 
+	/*
+	 * CBDB: for a foreign table, do not inherit source table's distribution policy.
+	 * It should be decided by OPTIONS, ex: mpp_execute all segments.
+	 */
+#if 0
 	if (IsA(stmt, CreateForeignTableStmt))
 	{
 		DistributedBy *ft_distributedBy = ((CreateForeignTableStmt *)stmt)->distributedBy;
 		if (ft_distributedBy || likeDistributedBy)
 			stmt->distributedBy = transformDistributedBy(pstate, &cxt, ft_distributedBy,
 														 likeDistributedBy, bQuiet);
 	}
+#endif
 
 	/*
 	 * Postprocess check constraints.
@@ -1071,11 +1077,16 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("LIKE INCLUDING may not be used with this kind of relation")));
 
+	/*
+	 * CBDB: Support CREATE FOREIGN TABLE LIKE.
+	 */
+#if 0
 	/* we could support LIKE in many cases, but worry about it another day */
 	if (cxt->isforeign)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("LIKE is not supported for creating foreign tables")));
+#endif
 
 	/* Open the relation referenced by the LIKE clause */
 	relation = relation_openrv(table_like_clause->relation, AccessShareLock);

src/test/regress/expected/gp_foreign_data.out

@@ -39,6 +39,44 @@ CREATE FOREIGN TABLE ft5 (
 Server: s1
 FDW options: (delimiter ',', mpp_execute 'all segments', num_segments '5')
 
+-- CREATE FOREIGN TABLE LIKE
+CREATE TABLE ft_source_table(a INT, b INT, c INT) DISTRIBUTED BY (b);
+CREATE FOREIGN TABLE ft_like (LIKE ft_source_table) SERVER s0; 
+\d+ ft_like
+                                     Foreign table "public.ft_like"
+ Column |  Type   | Collation | Nullable | Default | FDW options | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+-------------+---------+--------------+-------------
+ a      | integer |           |          |         |             | plain   |              | 
+ b      | integer |           |          |         |             | plain   |              | 
+ c      | integer |           |          |         |             | plain   |              | 
+Server: s0
+
+-- shoule be null
+SELECT * FROM gp_distribution_policy WHERE localoid = 'ft_like'::regclass::oid;
+ localoid | policytype | numsegments | distkey | distclass 
+----------+------------+-------------+---------+-----------
+(0 rows)
+
+CREATE FOREIGN TABLE ft_like1 (LIKE ft_source_table) SERVER s0
+OPTIONS (delimiter ',', mpp_execute 'all segments', num_segments '3');
+\d+ ft_like1
+                                    Foreign table "public.ft_like1"
+ Column |  Type   | Collation | Nullable | Default | FDW options | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+-------------+---------+--------------+-------------
+ a      | integer |           |          |         |             | plain   |              | 
+ b      | integer |           |          |         |             | plain   |              | 
+ c      | integer |           |          |         |             | plain   |              | 
+Server: s0
+FDW options: (delimiter ',', mpp_execute 'all segments', num_segments '3')
+
+SELECT * FROM gp_distribution_policy WHERE localoid = 'ft_like1'::regclass::oid;
+ localoid | policytype | numsegments | distkey | distclass 
+----------+------------+-------------+---------+-----------
+(0 rows)
+
+DROP TABLE ft_source_table;
+DROP FOREIGN TABLE ft_like;
+DROP FOREIGN TABLE ft_like1;
 --start_ignore
 DROP FOREIGN DATA WRAPPER dummy CASCADE;
 --end_ignore

src/test/regress/sql/gp_foreign_data.sql

@@ -28,6 +28,21 @@ CREATE FOREIGN TABLE ft5 (
 ) SERVER s1 OPTIONS (delimiter ',', mpp_execute 'all segments', num_segments '5');
 \d+ ft5
 
+-- CREATE FOREIGN TABLE LIKE
+CREATE TABLE ft_source_table(a INT, b INT, c INT) DISTRIBUTED BY (b);
+CREATE FOREIGN TABLE ft_like (LIKE ft_source_table) SERVER s0; 
+\d+ ft_like
+-- shoule be null
+SELECT * FROM gp_distribution_policy WHERE localoid = 'ft_like'::regclass::oid;
+CREATE FOREIGN TABLE ft_like1 (LIKE ft_source_table) SERVER s0
+OPTIONS (delimiter ',', mpp_execute 'all segments', num_segments '3');
+\d+ ft_like1
+SELECT * FROM gp_distribution_policy WHERE localoid = 'ft_like1'::regclass::oid;
+
+DROP TABLE ft_source_table;
+DROP FOREIGN TABLE ft_like;
+DROP FOREIGN TABLE ft_like1;
+
 --start_ignore
 DROP FOREIGN DATA WRAPPER dummy CASCADE;
 --end_ignore