Skip FK check when do relation truncate

GPDB does not support FK, but keep FK grammar in DDL, since it
reduce DB migration manual workload from others.
Hence, we do not need FK check for truncate command, rid of it.

src/backend/catalog/heap.c

@@ -3305,8 +3305,15 @@ heap_truncate(List *relids)
 		}
 	}
 
+	/* GPDB does not support all FK feature but keeps FK grammar recognition,
+	 * which reduces migration manual workload from other databases.
+	 * We do not want to reject relation truncate if the relation contains FK
+	 * satisfied tuple, so skip heap_truncate_check_FKs function call.
+	 */
+#if 0
 	/* Don't allow truncate on tables that are referenced by foreign keys */
 	heap_truncate_check_FKs(relations, true);
+#endif
 
 	/* OK to do it */
 	foreach(cell, relations)

src/backend/commands/tablecmds.c

@@ -1218,6 +1218,12 @@ ExecuteTruncate(TruncateStmt *stmt)
 		}
 	}
 
+	/* GPDB does not support all FK feature but keeps FK grammar recognition,
+	 * which reduces migration manual workload from other databases.
+	 * We do not want to reject relation truncate if the relation contains FK
+	 * satisfied tuple, so skip heap_truncate_check_FKs function call.
+	 */
+#if 0
 	/*
 	 * Check foreign key references.  In CASCADE mode, this should be
 	 * unnecessary since we just pulled in all the references; but as a
@@ -1228,6 +1234,7 @@ ExecuteTruncate(TruncateStmt *stmt)
 #else
 	if (truncateStatement->behavior == DROP_RESTRICT)
 		heap_truncate_check_FKs(rels, false);
+#endif
 #endif
 
 	/*

src/test/regress/expected/temp.out

@@ -165,8 +165,6 @@ NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "temptest3_pkey"
 CREATE TEMP TABLE temptest4(col int REFERENCES temptest3);
 WARNING:  Referential integrity (FOREIGN KEY) constraints are not supported in Greenplum Database, will not be enforced.
 COMMIT;
-ERROR:  unsupported ON COMMIT and foreign key combination
-DETAIL:  Table "temptest4" references "temptest3", but they do not have the same ON COMMIT setting.
 -- Test manipulation of temp schema's placement in search path
 create table public.whereami (f1 text);
 insert into public.whereami values ('public');

src/test/regress/expected/truncate.out

@@ -48,36 +48,15 @@ HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sur
 WARNING:  Referential integrity (FOREIGN KEY) constraints are not supported in Greenplum Database, will not be enforced.
 WARNING:  Referential integrity (FOREIGN KEY) constraints are not supported in Greenplum Database, will not be enforced.
 TRUNCATE TABLE truncate_a;		-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_b" references "truncate_a".
-HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE truncate_a,trunc_b;		-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_e" references "truncate_a".
-HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE truncate_a,trunc_b,trunc_e;	-- ok
 TRUNCATE TABLE truncate_a,trunc_e;		-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_b" references "truncate_a".
-HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c;		-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_d" references "trunc_c".
-HINT:  Truncate table "trunc_d" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,trunc_d;		-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_e" references "trunc_c".
-HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,trunc_d,trunc_e;	-- ok
 TRUNCATE TABLE trunc_c,trunc_d,trunc_e,truncate_a;	-- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_b" references "truncate_a".
-HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,trunc_d,trunc_e,truncate_a,trunc_b;	-- ok
 TRUNCATE TABLE truncate_a RESTRICT; -- fail
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_b" references "truncate_a".
-HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE truncate_a CASCADE;  -- ok
 NOTICE:  truncate cascades to table "trunc_b"
 NOTICE:  truncate cascades to table "trunc_e"
@@ -91,21 +70,9 @@ INSERT INTO trunc_b VALUES (1);
 INSERT INTO trunc_d VALUES (1);
 INSERT INTO trunc_e VALUES (1,1);
 TRUNCATE TABLE trunc_c;
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "truncate_a" references "trunc_c".
-HINT:  Truncate table "truncate_a" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,truncate_a;
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_d" references "trunc_c".
-HINT:  Truncate table "trunc_d" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,truncate_a,trunc_d;
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_e" references "trunc_c".
-HINT:  Truncate table "trunc_e" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,truncate_a,trunc_d,trunc_e;
-ERROR:  cannot truncate a table referenced in a foreign key constraint
-DETAIL:  Table "trunc_b" references "truncate_a".
-HINT:  Truncate table "trunc_b" at the same time, or use TRUNCATE ... CASCADE.
 TRUNCATE TABLE trunc_c,truncate_a,trunc_d,trunc_e,trunc_b;
 -- Verify that truncating did actually work
 SELECT * FROM truncate_a