concurrent master_append_table test is added

src/test/regress/isolation_schedule

@@ -38,3 +38,4 @@ test: isolation_delete_vs_all
 test: isolation_truncate_vs_all
 test: isolation_drop_vs_all
 test: isolation_ddl_vs_all
+test: isolation_master_append_table

src/test/regress/specs/isolation_master_append_table.spec

@@ -0,0 +1,64 @@
+setup
+{	
+	ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 230000;
+
+  	CREATE TABLE table_to_append(id int);
+  	CREATE TABLE table_to_be_appended(id int);
+
+  	SELECT create_distributed_table('table_to_append', 'id', 'append');
+  	INSERT INTO table_to_be_appended VALUES(0),(1),(2),(3),(4),(5);
+
+  	COPY table_to_append FROM PROGRAM 'echo "1\n2\n3\n4\n5"';
+}
+
+teardown
+{
+	DROP TABLE table_to_append CASCADE;
+	DROP TABLE table_to_be_appended CASCADE;
+}
+
+session "s1"
+
+step "s1-begin"
+{
+    BEGIN;
+}
+
+step "s1-master_append_table_to_shard"
+{
+   	SELECT	
+   		master_append_table_to_shard(shardid, 'table_to_be_appended', 'localhost', 57636)
+	FROM
+		pg_dist_shard
+	WHERE
+		'table_to_append'::regclass::oid = logicalrelid;
+}
+
+step "s1-commit"
+{
+    COMMIT;
+}
+
+session "s2"
+
+step "s2-begin"
+{
+	BEGIN;
+}
+
+step "s2-master_append_table_to_shard"
+{
+
+   	SELECT	
+   		master_append_table_to_shard(shardid, 'table_to_be_appended', 'localhost', 57636)
+	FROM
+		pg_dist_shard
+	WHERE
+		'table_to_append'::regclass::oid = logicalrelid;
+}
+step "s2-commit"
+{
+	COMMIT;
+}
+
+permutation "s1-begin" "s2-begin" "s1-master_append_table_to_shard" "s2-master_append_table_to_shard" "s1-commit" "s2-commit"