Block multi-statement DDL command in one query

Ensure that queries involving several distributed DDL commands
in one query string are blocked.

Fix #4818

tsl/src/remote/dist_ddl.c

@@ -116,6 +116,21 @@ dist_ddl_error_if_not_allowed_data_node_session(void)
 	dist_ddl_error_raise_blocked();
 }
 
+static void
+dist_ddl_error_if_multi_command(const ProcessUtilityArgs *args)
+{
+	List *parsetree_list;
+
+	/* Parse the SQL string into a list of raw parse trees */
+	parsetree_list = pg_parse_query(args->query_string);
+
+	/* Prevent 'command;command' execution */
+	if (list_length(parsetree_list) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("nested commands are not supported on distributed hypertable")));
+}
+
 static void
 dist_ddl_state_add_remote_command(const char *cmd)
 {
@@ -314,6 +329,9 @@ dist_ddl_state_set_hypertable(const ProcessUtilityArgs *args)
 	if (num_hypertables > 1)
 		dist_ddl_error_raise_unsupported();
 
+	/* Prevent execution of several commands in one query string */
+	dist_ddl_error_if_multi_command(args);
+
 	/* Get the distributed hypertable */
 	ht =
 		ts_hypertable_cache_get_entry(hcache, linitial_oid(args->hypertable_list), CACHE_FLAG_NONE);

tsl/test/expected/dist_ddl.out

@@ -2539,6 +2539,31 @@ INSERT INTO hyper SELECT t, ceil((random() * 5))::int, random() * 80
 FROM generate_series('2019-01-01'::timestamptz, '2019-01-05'::timestamptz, '1 minute') as t;
 ANALYZE hyper;
 --
+-- Ensure single query multi-statement command is blocked
+--
+-- Issue #4818
+--
+CREATE TABLE disttable(time timestamptz NOT NULL, device int);
+SELECT * FROM create_distributed_hypertable('disttable', 'time', 'device');
+ hypertable_id | schema_name | table_name | created 
+---------------+-------------+------------+---------
+            21 | public      | disttable  | t
+(1 row)
+
+CREATE OR REPLACE PROCEDURE test_dist_multi_stmt_command()
+LANGUAGE plpgsql AS $$
+BEGIN
+    EXECUTE 'ANALYZE disttable; ANALYZE disttable';
+END
+$$;
+SET timescaledb.hide_data_node_name_in_errors = 'on';
+-- unsupported
+\set ON_ERROR_STOP 0
+CALL test_dist_multi_stmt_command();
+ERROR:  nested commands are not supported on distributed hypertable
+\set ON_ERROR_STOP 1
+DROP TABLE disttable;
+--
 -- Test hypertable distributed defaults
 --
 SHOW timescaledb.hypertable_distributed_default;
@@ -2563,7 +2588,7 @@ ERROR:  local hypertables cannot set replication_factor
 SELECT create_hypertable('drf_test', 'time', distributed=>true, replication_factor=>1);
    create_hypertable    
 ------------------------
- (21,public,drf_test,t)
+ (22,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2581,7 +2606,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', distributed=>false);
    create_hypertable    
 ------------------------
- (22,public,drf_test,t)
+ (23,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2596,7 +2621,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', distributed=>true);
    create_hypertable    
 ------------------------
- (23,public,drf_test,t)
+ (24,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2613,7 +2638,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', distributed=>false);
    create_hypertable    
 ------------------------
- (24,public,drf_test,t)
+ (25,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2628,7 +2653,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', distributed=>true);
    create_hypertable    
 ------------------------
- (25,public,drf_test,t)
+ (26,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2652,7 +2677,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', distributed=>true);
    create_hypertable    
 ------------------------
- (26,public,drf_test,t)
+ (27,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2670,7 +2695,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', replication_factor=>2);
    create_hypertable    
 ------------------------
- (27,public,drf_test,t)
+ (28,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2687,7 +2712,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time', replication_factor=>2);
    create_hypertable    
 ------------------------
- (28,public,drf_test,t)
+ (29,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2721,7 +2746,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time');
    create_hypertable    
 ------------------------
- (29,public,drf_test,t)
+ (30,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2738,7 +2763,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time');
    create_hypertable    
 ------------------------
- (30,public,drf_test,t)
+ (31,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';
@@ -2756,7 +2781,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_hypertable('drf_test', 'time');
    create_hypertable    
 ------------------------
- (31,public,drf_test,t)
+ (32,public,drf_test,t)
 (1 row)
 
 DROP TABLE drf_test;
@@ -2768,7 +2793,7 @@ CREATE TABLE drf_test(time TIMESTAMPTZ NOT NULL);
 SELECT create_distributed_hypertable('drf_test', 'time');
  create_distributed_hypertable 
 -------------------------------
- (32,public,drf_test,t)
+ (33,public,drf_test,t)
 (1 row)
 
 SELECT is_distributed, replication_factor FROM timescaledb_information.hypertables WHERE hypertable_name = 'drf_test';

tsl/test/sql/dist_ddl.sql

@@ -730,6 +730,29 @@ INSERT INTO hyper SELECT t, ceil((random() * 5))::int, random() * 80
 FROM generate_series('2019-01-01'::timestamptz, '2019-01-05'::timestamptz, '1 minute') as t;
 ANALYZE hyper;
 
+--
+-- Ensure single query multi-statement command is blocked
+--
+-- Issue #4818
+--
+CREATE TABLE disttable(time timestamptz NOT NULL, device int);
+SELECT * FROM create_distributed_hypertable('disttable', 'time', 'device');
+
+CREATE OR REPLACE PROCEDURE test_dist_multi_stmt_command()
+LANGUAGE plpgsql AS $$
+BEGIN
+    EXECUTE 'ANALYZE disttable; ANALYZE disttable';
+END
+$$;
+
+SET timescaledb.hide_data_node_name_in_errors = 'on';
+
+-- unsupported
+\set ON_ERROR_STOP 0
+CALL test_dist_multi_stmt_command();
+\set ON_ERROR_STOP 1
+
+DROP TABLE disttable;
 --
 -- Test hypertable distributed defaults
 --