Merge pull request #2150 from citusdata/modify_volatility_check

Check volatile functions in modify queries

src/backend/distributed/planner/multi_router_planner.c

@@ -939,6 +939,13 @@ MultiShardModifyQuerySupported(Query *originalQuery,
 									 "ON instead",
 									 NULL, NULL);
 	}
+	else if (FindNodeCheck((Node *) originalQuery, CitusIsVolatileFunction))
+	{
+		errorMessage = DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
+									 "functions used in UPDATE queries on distributed "
+									 "tables must not be VOLATILE",
+									 NULL, NULL);
+	}
 	else if (resultPartitionMethod == DISTRIBUTE_BY_NONE)
 	{
 		errorMessage = DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,

src/test/regress/expected/multi_shard_update_delete.out

@@ -699,10 +699,26 @@ SET    value_2 = 5 * random()
 FROM   events_test_table
 WHERE  users_test_table.user_id = events_test_table.user_id;
 ERROR:  functions used in UPDATE queries on distributed tables must not be VOLATILE
+-- Recursive modify planner does not take care of following test because the query
+-- is fully pushdownable, yet not allowed because it would lead to inconsistent replicas.
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+ERROR:  functions used in UPDATE queries on distributed tables must not be VOLATILE
 -- Volatile functions in a subquery are recursively planned
 UPDATE users_test_table
 SET    value_2 = 5
 WHERE  users_test_table.user_id IN (SELECT user_id * random() FROM events_test_table);
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery;
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table OFFSET 0) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+-- Make following tests consistent
+UPDATE users_test_table SET value_2 = 0;
 -- Local tables are not supported
 UPDATE users_test_table
 SET    value_2 = 5
@@ -738,7 +754,7 @@ DECLARE test_cursor CURSOR FOR SELECT * FROM users_test_table;
 FETCH test_cursor;
  user_id | value_1 | value_2 | value_3 
 ---------+---------+---------+---------
-       8 |       4 |      13 |       0
+       8 |       4 |       0 |       0
 (1 row)
 
 UPDATE users_test_table SET value_2 = 5 WHERE CURRENT OF test_cursor;

src/test/regress/expected/multi_shard_update_delete_0.out

@@ -722,10 +722,26 @@ SET    value_2 = 5 * random()
 FROM   events_test_table
 WHERE  users_test_table.user_id = events_test_table.user_id;
 ERROR:  functions used in UPDATE queries on distributed tables must not be VOLATILE
+-- Recursive modify planner does not take care of following test because the query
+-- is fully pushdownable, yet not allowed because it would lead to inconsistent replicas.
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+ERROR:  functions used in UPDATE queries on distributed tables must not be VOLATILE
 -- Volatile functions in a subquery are recursively planned
 UPDATE users_test_table
 SET    value_2 = 5
 WHERE  users_test_table.user_id IN (SELECT user_id * random() FROM events_test_table);
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery;
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table OFFSET 0) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+-- Make following tests consistent
+UPDATE users_test_table SET value_2 = 0;
 -- Local tables are not supported
 UPDATE users_test_table
 SET    value_2 = 5
@@ -761,7 +777,7 @@ DECLARE test_cursor CURSOR FOR SELECT * FROM users_test_table;
 FETCH test_cursor;
  user_id | value_1 | value_2 | value_3 
 ---------+---------+---------+---------
-       8 |       4 |      13 |       0
+       8 |       4 |       0 |       0
 (1 row)
 
 UPDATE users_test_table SET value_2 = 5 WHERE CURRENT OF test_cursor;

src/test/regress/sql/multi_shard_update_delete.sql

@@ -580,11 +580,30 @@ SET    value_2 = 5 * random()
 FROM   events_test_table
 WHERE  users_test_table.user_id = events_test_table.user_id;
 
+-- Recursive modify planner does not take care of following test because the query
+-- is fully pushdownable, yet not allowed because it would lead to inconsistent replicas.
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+
 -- Volatile functions in a subquery are recursively planned
 UPDATE users_test_table
 SET    value_2 = 5
 WHERE  users_test_table.user_id IN (SELECT user_id * random() FROM events_test_table);
 
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table) subquery;
+
+UPDATE users_test_table
+SET    value_2 = subquery.random FROM (SELECT user_id, random()
+                                       FROM events_test_table OFFSET 0) subquery
+WHERE  users_test_table.user_id = subquery.user_id;
+
+-- Make following tests consistent
+UPDATE users_test_table SET value_2 = 0;
+
 -- Local tables are not supported
 UPDATE users_test_table
 SET    value_2 = 5