Skip GENERATED AS ALWAYS STORED cols when processing cols owning sequences

When finding columns owning sequences, we shouldn't rely on atthasdef
since it might be true when column has GENERATED ALWAYS AS (...)
STORED expression.

src/backend/distributed/commands/sequence.c

@@ -177,6 +177,14 @@ ExtractColumnsOwningSequences(Oid relationId, List **columnNameList,
 			continue;
 		}
 
+#if PG_VERSION_NUM >= PG_VERSION_12
+		if (attributeForm->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		{
+			/* skip columns with GENERATED AS ALWAYS expressions */
+			continue;
+		}
+#endif
+
 		char *columnName = NameStr(attributeForm->attname);
 		*columnNameList = lappend(*columnNameList, columnName);
 

src/test/regress/expected/pg12.out

@@ -411,6 +411,52 @@ where val = 'asdf';
      3
 (1 row)
 
+-- not replicate reference tables from other test files
+SET citus.replicate_reference_tables_on_activate TO off;
+SELECT 1 FROM citus_add_node('localhost', :master_port, groupId => 0);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+BEGIN;
+  CREATE TABLE generated_stored_col_test (x int, y int generated always as (x+1) stored);
+  SELECT citus_add_local_table_to_metadata('generated_stored_col_test');
+ citus_add_local_table_to_metadata
+---------------------------------------------------------------------
+
+(1 row)
+
+  -- simply check if GENERATED ALWAYS AS (...) STORED expression works fine
+  INSERT INTO generated_stored_col_test VALUES(1), (2);
+  SELECT * FROM generated_stored_col_test ORDER BY 1,2;
+ x | y
+---------------------------------------------------------------------
+ 1 | 2
+ 2 | 3
+(2 rows)
+
+  -- show that we keep such expressions on shell relation and shard relation
+  SELECT s.relname, a.attname, a.attgenerated
+  FROM pg_class s
+  JOIN pg_attribute a ON a.attrelid=s.oid
+  WHERE s.relname LIKE 'generated_stored_col_test%' AND
+        attname = 'y'
+  ORDER BY 1,2;
+             relname             | attname | attgenerated
+---------------------------------------------------------------------
+ generated_stored_col_test       | y       | s
+ generated_stored_col_test_60040 | y       | s
+(2 rows)
+
+ROLLBACK;
+RESET citus.replicate_reference_tables_on_activate;
+SELECT citus_remove_node('localhost', :master_port);
+ citus_remove_node
+---------------------------------------------------------------------
+
+(1 row)
+
 \set VERBOSITY terse
 drop schema test_pg12 cascade;
 NOTICE:  drop cascades to 10 other objects

src/test/regress/sql/pg12.sql

@@ -275,6 +275,30 @@ select count(*)
 from col_test
 where val = 'asdf';
 
+-- not replicate reference tables from other test files
+SET citus.replicate_reference_tables_on_activate TO off;
+SELECT 1 FROM citus_add_node('localhost', :master_port, groupId => 0);
+
+BEGIN;
+  CREATE TABLE generated_stored_col_test (x int, y int generated always as (x+1) stored);
+  SELECT citus_add_local_table_to_metadata('generated_stored_col_test');
+
+  -- simply check if GENERATED ALWAYS AS (...) STORED expression works fine
+  INSERT INTO generated_stored_col_test VALUES(1), (2);
+  SELECT * FROM generated_stored_col_test ORDER BY 1,2;
+
+  -- show that we keep such expressions on shell relation and shard relation
+  SELECT s.relname, a.attname, a.attgenerated
+  FROM pg_class s
+  JOIN pg_attribute a ON a.attrelid=s.oid
+  WHERE s.relname LIKE 'generated_stored_col_test%' AND
+        attname = 'y'
+  ORDER BY 1,2;
+ROLLBACK;
+
+RESET citus.replicate_reference_tables_on_activate;
+SELECT citus_remove_node('localhost', :master_port);
+
 \set VERBOSITY terse
 drop schema test_pg12 cascade;
 \set VERBOSITY default