Merge pull request #5127 from citusdata/get_ready_tenant_isolation

Introduce citus_internal_delete_shard_metadata

src/backend/distributed/metadata/metadata_sync.c

@@ -127,6 +127,7 @@ PG_FUNCTION_INFO_V1(citus_internal_add_partition_metadata);
 PG_FUNCTION_INFO_V1(citus_internal_add_shard_metadata);
 PG_FUNCTION_INFO_V1(citus_internal_add_placement_metadata);
 PG_FUNCTION_INFO_V1(citus_internal_update_placement_metadata);
+PG_FUNCTION_INFO_V1(citus_internal_delete_shard_metadata);
 
 
 static bool got_SIGTERM = false;
@@ -2255,8 +2256,8 @@ EnsureCoordinatorInitiatedOperation(void)
 		GetLocalGroupId() == COORDINATOR_GROUP_ID)
 	{
 		ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-						errmsg("This is an internal function that only Citus "
-							   "requires to use in a distributed transaction")));
+						errmsg("This is an internal Citus function can only be "
+							   "used in a distributed transaction")));
 	}
 }
 
@@ -2573,3 +2574,41 @@ citus_internal_update_placement_metadata(PG_FUNCTION_ARGS)
 
 	PG_RETURN_VOID();
 }
+
+
+/*
+ * citus_internal_delete_shard_metadata is an internal UDF to
+ * delete a row in pg_dist_shard and corresponding placement rows
+ * from pg_dist_shard_placement.
+ */
+Datum
+citus_internal_delete_shard_metadata(PG_FUNCTION_ARGS)
+{
+	int64 shardId = PG_GETARG_INT64(0);
+
+	if (!ShouldSkipMetadataChecks())
+	{
+		/* this UDF is not allowed allowed for executing as a separate command */
+		EnsureCoordinatorInitiatedOperation();
+
+		if (!ShardExists(shardId))
+		{
+			ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+							errmsg("Shard id does not exists: %ld", shardId)));
+		}
+
+		bool missingOk = false;
+		EnsureShardOwner(shardId, missingOk);
+	}
+
+	List *shardPlacementList = ShardPlacementListIncludingOrphanedPlacements(shardId);
+	ShardPlacement *shardPlacement = NULL;
+	foreach_ptr(shardPlacement, shardPlacementList)
+	{
+		DeleteShardPlacementRow(shardPlacement->placementId);
+	}
+
+	DeleteShardRow(shardId);
+
+	PG_RETURN_VOID();
+}

src/backend/distributed/sql/citus--10.1-1--10.2-1.sql

@@ -14,3 +14,4 @@ ALTER TABLE pg_catalog.pg_dist_placement ADD CONSTRAINT placement_shardid_groupi
 #include "udfs/citus_internal_add_shard_metadata/10.2-1.sql";
 #include "udfs/citus_internal_add_placement_metadata/10.2-1.sql";
 #include "udfs/citus_internal_update_placement_metadata/10.2-1.sql";
+#include "udfs/citus_internal_delete_shard_metadata/10.2-1.sql";

src/backend/distributed/sql/downgrades/citus--10.2-1--10.1-1.sql

@@ -15,6 +15,7 @@ DROP FUNCTION pg_catalog.citus_internal_add_partition_metadata(regclass, "char",
 DROP FUNCTION pg_catalog.citus_internal_add_shard_metadata(regclass, bigint, "char", text, text);
 DROP FUNCTION pg_catalog.citus_internal_add_placement_metadata(bigint, integer, bigint, integer, bigint);
 DROP FUNCTION pg_catalog.citus_internal_update_placement_metadata(bigint, integer, integer);
+DROP FUNCTION pg_catalog.citus_internal_delete_shard_metadata(bigint);
 
 REVOKE ALL ON FUNCTION pg_catalog.worker_record_sequence_dependency(regclass,regclass,name) FROM PUBLIC;
 ALTER TABLE pg_catalog.pg_dist_placement DROP CONSTRAINT placement_shardid_groupid_unique_index;

src/backend/distributed/sql/udfs/citus_internal_delete_shard_metadata/10.2-1.sql

@@ -0,0 +1,7 @@
+CREATE OR REPLACE FUNCTION pg_catalog.citus_internal_delete_shard_metadata(shard_id bigint)
+    RETURNS void
+    LANGUAGE C STRICT
+    AS 'MODULE_PATHNAME';
+COMMENT ON FUNCTION pg_catalog.citus_internal_delete_shard_metadata(bigint) IS
+    'Deletes rows from pg_dist_shard and pg_dist_shard_placement with user checks';
+

src/backend/distributed/sql/udfs/citus_internal_delete_shard_metadata/latest.sql

@@ -0,0 +1,7 @@
+CREATE OR REPLACE FUNCTION pg_catalog.citus_internal_delete_shard_metadata(shard_id bigint)
+    RETURNS void
+    LANGUAGE C STRICT
+    AS 'MODULE_PATHNAME';
+COMMENT ON FUNCTION pg_catalog.citus_internal_delete_shard_metadata(bigint) IS
+    'Deletes rows from pg_dist_shard and pg_dist_shard_placement with user checks';
+

src/test/regress/expected/metadata_sync_helpers.out

@@ -13,7 +13,7 @@ SET search_path TO metadata_sync_helpers;
 CREATE TABLE test(col_1 int);
 -- not in a distributed transaction
 SELECT citus_internal_add_partition_metadata ('test'::regclass, 'h', 'col_1', 0, 's');
-ERROR:  This is an internal function that only Citus requires to use in a distributed transaction
+ERROR:  This is an internal Citus function can only be used in a distributed transaction
 -- in a distributed transaction, but the application name is not Citus
 BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
 	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
@@ -23,7 +23,7 @@ BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
 (1 row)
 
 	SELECT citus_internal_add_partition_metadata ('test'::regclass, 'h', 'col_1', 0, 's');
-ERROR:  This is an internal function that only Citus requires to use in a distributed transaction
+ERROR:  This is an internal Citus function can only be used in a distributed transaction
 ROLLBACK;
 -- in a distributed transaction and the application name is Citus
 -- but we are on the coordinator, so still not allowed
@@ -36,7 +36,7 @@ BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
 
 	SET application_name to 'citus';
 	SELECT citus_internal_add_partition_metadata ('test'::regclass, 'h', 'col_1', 0, 's');
-ERROR:  This is an internal function that only Citus requires to use in a distributed transaction
+ERROR:  This is an internal Citus function can only be used in a distributed transaction
 ROLLBACK;
 -- connect back as super user, and then connect to the worker
 -- with the superuser to make sure we can ingest metadata with
@@ -886,6 +886,88 @@ BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
 	SELECT citus_internal_update_placement_metadata(1420007, get_node_id(), get_node_id()+1);
 ERROR:  must be owner of table super_user_table
 COMMIT;
+-- the user only allowed to delete their own shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+ assign_distributed_transaction_id
+---------------------------------------------------------------------
+
+(1 row)
+
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420007))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ERROR:  must be owner of table super_user_table
+ROLLBACK;
+-- the user only allowed to delete shards in a distributed transaction
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420007))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ERROR:  This is an internal Citus function can only be used in a distributed transaction
+ROLLBACK;
+-- the user cannot delete non-existing shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+ assign_distributed_transaction_id
+---------------------------------------------------------------------
+
+(1 row)
+
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420100))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ERROR:  Shard id does not exists: 1420100
+ROLLBACK;
+-- sucessfully delete shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SELECT count(*) FROM pg_dist_shard WHERE shardid = 1420000;
+ count
+---------------------------------------------------------------------
+     1
+(1 row)
+
+	SELECT count(*) FROM pg_dist_placement WHERE shardid = 1420000;
+ count
+---------------------------------------------------------------------
+     1
+(1 row)
+
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+ assign_distributed_transaction_id
+---------------------------------------------------------------------
+
+(1 row)
+
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420000))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ citus_internal_delete_shard_metadata
+---------------------------------------------------------------------
+
+(1 row)
+
+	SELECT count(*) FROM pg_dist_shard WHERE shardid = 1420000;
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
+	SELECT count(*) FROM pg_dist_placement WHERE shardid = 1420000;
+ count
+---------------------------------------------------------------------
+     0
+(1 row)
+
+ROLLBACK;
 -- we don't need the table/schema anymore
 -- connect back as super user to drop everything
 \c - postgres - :worker_1_port

src/test/regress/expected/multi_extension.out

@@ -649,9 +649,10 @@ SELECT * FROM multi_extension.print_extension_changes();
                                                         | function citus_internal_add_partition_metadata(regclass,"char",text,integer,"char") void
                                                         | function citus_internal_add_placement_metadata(bigint,integer,bigint,integer,bigint) void
                                                         | function citus_internal_add_shard_metadata(regclass,bigint,"char",text,text) void
+                                                        | function citus_internal_delete_shard_metadata(bigint) void
                                                         | function citus_internal_update_placement_metadata(bigint,integer,integer) void
                                                         | function stop_metadata_sync_to_node(text,integer,boolean) void
-(8 rows)
+(9 rows)
 
 DROP TABLE multi_extension.prev_objects, multi_extension.extension_diff;
 -- show running version

src/test/regress/expected/upgrade_list_citus_objects.out

@@ -69,6 +69,7 @@ ORDER BY 1;
  function citus_internal_add_partition_metadata(regclass,"char",text,integer,"char")
  function citus_internal_add_placement_metadata(bigint,integer,bigint,integer,bigint)
  function citus_internal_add_shard_metadata(regclass,bigint,"char",text,text)
+ function citus_internal_delete_shard_metadata(bigint)
  function citus_internal_update_placement_metadata(bigint,integer,integer)
  function citus_isolation_test_session_is_blocked(integer,integer[])
  function citus_json_concatenate(json,json)
@@ -252,5 +253,5 @@ ORDER BY 1;
  view citus_worker_stat_activity
  view pg_dist_shard_placement
  view time_partitions
-(236 rows)
+(237 rows)
 

src/test/regress/sql/metadata_sync_helpers.sql

@@ -572,6 +572,53 @@ BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
 	SELECT citus_internal_update_placement_metadata(1420007, get_node_id(), get_node_id()+1);
 COMMIT;
 
+-- the user only allowed to delete their own shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420007))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ROLLBACK;
+
+-- the user only allowed to delete shards in a distributed transaction
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420007))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ROLLBACK;
+
+-- the user cannot delete non-existing shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420100))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+ROLLBACK;
+
+
+-- sucessfully delete shards
+BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;
+
+	SELECT count(*) FROM pg_dist_shard WHERE shardid = 1420000;
+	SELECT count(*) FROM pg_dist_placement WHERE shardid = 1420000;
+
+	SELECT assign_distributed_transaction_id(0, 8, '2021-07-09 15:41:55.542377+02');
+	SET application_name to 'citus';
+	\set VERBOSITY terse
+	WITH shard_data(shardid)
+		AS (VALUES (1420000))
+	SELECT citus_internal_delete_shard_metadata(shardid) FROM shard_data;
+
+	SELECT count(*) FROM pg_dist_shard WHERE shardid = 1420000;
+	SELECT count(*) FROM pg_dist_placement WHERE shardid = 1420000;
+ROLLBACK;
+
 -- we don't need the table/schema anymore
 -- connect back as super user to drop everything
 \c - postgres - :worker_1_port