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Prevent Citus table functions from being called on shards (Fix #5610) (#5694) 

DESCRIPTION: Prevent Citus table functions from being called on shards

The operations that guard against using shards are:
* Create Local Table
* Create distributed table (which affects reference table creation as well).

* I used a `ErrorIfRaltionIsKnownShard` instead of `ErrorIfIllegallyChangingKnownShard`.
`ErrorIfIllegallyChangingKnownShard` allows the operation if `citus.enable_manual_changes_to_shards`,
but I am not sure if it ever makes sense to create a distributed, reference, or citus local table out of a shard.

I tried to go over the code to identify other UDF-s where shards could be illegaly changed, but I could not find any other.
My knowledge of the codebase is not solid enough for me to say for sure.

Fixes #5610
pull/5704/head
Gledis Zeneli 2022-02-14 16:06:48 +03:00 committed by GitHub
parent 8a3544b4d9
commit badfd561b2
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 63 additions and 20 deletions
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10
src/backend/distributed/commands/create_distributed_table.c
View File

@ -60,6 +60,7 @@
#include "distributed/remote_commands.h"
#include "distributed/shared_library_init.h"
#include "distributed/worker_protocol.h"
#include "distributed/worker_shard_visibility.h"
#include "distributed/worker_transaction.h"
#include "distributed/version_compat.h"
#include "executor/executor.h"
@ -327,6 +328,7 @@ create_reference_table(PG_FUNCTION_ARGS)
* - we are on the coordinator
* - the current user is the owner of the table
* - relation kind is supported
* - relation is not a shard
*/
static void
EnsureCitusTableCanBeCreated(Oid relationOid)
@ -343,6 +345,14 @@ EnsureCitusTableCanBeCreated(Oid relationOid)
* will be performed in CreateDistributedTable.
*/
EnsureRelationKindSupported(relationOid);
/*
* When coordinator is added to the metadata, or on the workers,
* some of the relations of the coordinator node may/will be shards.
* We disallow creating distributed tables from shard relations, by
* erroring out here.
*/
ErrorIfRelationIsAKnownShard(relationOid);
}

22
src/test/regress/expected/single_node.out
View File

@ -2011,8 +2011,28 @@ RESET citus.enable_manual_changes_to_shards ;
-- these should work as expected
TRUNCATE TABLE test_disabling_drop_and_truncate_102040;
DROP TABLE test_disabling_drop_and_truncate_102040;
RESET citus.shard_replication_factor;
DROP TABLE test_disabling_drop_and_truncate;
-- test creating distributed or reference tables from shards
CREATE TABLE test_creating_distributed_relation_table_from_shard (a int);
SELECT create_distributed_table('test_creating_distributed_relation_table_from_shard', 'a');
NOTICE: executing the command locally: SELECT worker_apply_shard_ddl_command (102044, 'single_node', 'CREATE TABLE single_node.test_creating_distributed_relation_table_from_shard (a integer) ');SELECT worker_apply_shard_ddl_command (102044, 'single_node', 'ALTER TABLE single_node.test_creating_distributed_relation_table_from_shard OWNER TO postgres')
NOTICE: executing the command locally: SELECT worker_apply_shard_ddl_command (102045, 'single_node', 'CREATE TABLE single_node.test_creating_distributed_relation_table_from_shard (a integer) ');SELECT worker_apply_shard_ddl_command (102045, 'single_node', 'ALTER TABLE single_node.test_creating_distributed_relation_table_from_shard OWNER TO postgres')
NOTICE: executing the command locally: SELECT worker_apply_shard_ddl_command (102046, 'single_node', 'CREATE TABLE single_node.test_creating_distributed_relation_table_from_shard (a integer) ');SELECT worker_apply_shard_ddl_command (102046, 'single_node', 'ALTER TABLE single_node.test_creating_distributed_relation_table_from_shard OWNER TO postgres')
NOTICE: executing the command locally: SELECT worker_apply_shard_ddl_command (102047, 'single_node', 'CREATE TABLE single_node.test_creating_distributed_relation_table_from_shard (a integer) ');SELECT worker_apply_shard_ddl_command (102047, 'single_node', 'ALTER TABLE single_node.test_creating_distributed_relation_table_from_shard OWNER TO postgres')
create_distributed_table
---------------------------------------------------------------------
(1 row)
-- these should error because shards cannot be used to:
-- create distributed table
SELECT create_distributed_table('test_creating_distributed_relation_table_from_shard_102044', 'a');
ERROR: relation "test_creating_distributed_relation_table_from_shard_102044" is a shard relation
-- create reference table
SELECT create_reference_table('test_creating_distributed_relation_table_from_shard_102044');
ERROR: relation "test_creating_distributed_relation_table_from_shard_102044" is a shard relation
RESET citus.shard_replication_factor;
DROP TABLE test_creating_distributed_relation_table_from_shard;
-- lets flush the copy often to make sure everyhing is fine
SET citus.local_copy_flush_threshold TO 1;
TRUNCATE another_schema_table;

36
src/test/regress/expected/single_node_truncate.out
View File

@ -31,9 +31,9 @@ SELECT * FROM table_sizes;
name | has_data
---------------------------------------------------------------------
citus_local | f
citus_local_102045 | t
citus_local_102049 | t
ref | t
ref_102044 | t
ref_102048 | t
(4 rows)
-- verify that this UDF is noop on Citus local tables
@ -47,9 +47,9 @@ SELECT * FROM table_sizes;
name | has_data
---------------------------------------------------------------------
citus_local | f
citus_local_102045 | t
citus_local_102049 | t
ref | t
ref_102044 | t
ref_102048 | t
(4 rows)
-- test that we allow cascading truncates to citus local tables
@ -65,9 +65,9 @@ SELECT * FROM table_sizes;
name | has_data
---------------------------------------------------------------------
citus_local | f
citus_local_102045 | t
citus_local_102049 | t
ref | f
ref_102044 | t
ref_102048 | t
(4 rows)
ROLLBACK;
@ -98,14 +98,14 @@ SELECT * FROM table_sizes;
name | has_data
---------------------------------------------------------------------
citus_local | f
citus_local_102045 | t
citus_local_102049 | t
dist | f
dist_102047 | t
dist_102048 | t
dist_102049 | t
dist_102050 | t
dist_102051 | t
dist_102052 | t
dist_102053 | t
dist_102054 | t
ref | f
ref_102044 | t
ref_102048 | t
(9 rows)
ROLLBACK;
@ -121,14 +121,14 @@ SELECT * FROM table_sizes;
name | has_data
---------------------------------------------------------------------
citus_local | f
citus_local_102045 | t
citus_local_102049 | t
dist | f
dist_102047 | t
dist_102048 | t
dist_102049 | t
dist_102050 | t
dist_102051 | t
dist_102052 | t
dist_102053 | t
dist_102054 | t
ref | t
ref_102044 | t
ref_102048 | t
(9 rows)
ROLLBACK;

15
src/test/regress/sql/single_node.sql
View File

@ -1017,9 +1017,22 @@ RESET citus.enable_manual_changes_to_shards ;
TRUNCATE TABLE test_disabling_drop_and_truncate_102040;
DROP TABLE test_disabling_drop_and_truncate_102040;
RESET citus.shard_replication_factor;
DROP TABLE test_disabling_drop_and_truncate;
-- test creating distributed or reference tables from shards
CREATE TABLE test_creating_distributed_relation_table_from_shard (a int);
SELECT create_distributed_table('test_creating_distributed_relation_table_from_shard', 'a');
-- these should error because shards cannot be used to:
-- create distributed table
SELECT create_distributed_table('test_creating_distributed_relation_table_from_shard_102044', 'a');
-- create reference table
SELECT create_reference_table('test_creating_distributed_relation_table_from_shard_102044');
RESET citus.shard_replication_factor;
DROP TABLE test_creating_distributed_relation_table_from_shard;
-- lets flush the copy often to make sure everyhing is fine
SET citus.local_copy_flush_threshold TO 1;
TRUNCATE another_schema_table;