database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-11 20:28:21 +03:00
Code Activity

Add option to enable two_phase commits via pg_create_logical_replication_slot.

Browse Source 
Commit 0aa8a01d04 extends the output plugin API to allow decoding of
prepared xacts and allowed the user to enable/disable the two-phase option
via pg_logical_slot_get_changes(). This can lead to a problem such that
the first time when it gets changes via pg_logical_slot_get_changes()
without two_phase option enabled it will not get the prepared even though
prepare is after consistent snapshot. Now next time during getting changes,
if the two_phase option is enabled it can skip prepare because by that
time start decoding point has been moved. So the user will only get commit
prepared.

Allow to enable/disable this option at the create slot time and default
will be false. It will break the existing slots which is fine in a major
release.

Author: Ajin Cherian
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
This commit is contained in:
Amit Kapila
2021-03-03 07:28:43 +05:30
parent ee28cacf61
commit 19890a064e
20 changed files with 131 additions and 93 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
contrib/test_decoding/sql/twophase.sql
View File

@ -1,7 +1,7 @@
-- Test prepared transactions. When two-phase-commit is enabled, transactions are
-- decoded at PREPARE time rather than at COMMIT PREPARED time.
SET synchronous_commit = on;
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding', false, true);
CREATE TABLE test_prepared1(id integer primary key);
CREATE TABLE test_prepared2(id integer primary key);
@ -12,20 +12,20 @@ BEGIN;
INSERT INTO test_prepared1 VALUES (1);
INSERT INTO test_prepared1 VALUES (2);
-- should show nothing because the xact has not been prepared yet.
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
PREPARE TRANSACTION 'test_prepared#1';
-- should show both the above inserts and the PREPARE TRANSACTION.
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
COMMIT PREPARED 'test_prepared#1';
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test that rollback of a prepared xact is decoded.
BEGIN;
INSERT INTO test_prepared1 VALUES (3);
PREPARE TRANSACTION 'test_prepared#2';
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
ROLLBACK PREPARED 'test_prepared#2';
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test prepare of a xact containing ddl. Leaving xact uncommitted for next test.
BEGIN;
@ -38,7 +38,7 @@ FROM pg_locks
WHERE locktype = 'relation'
AND relation = 'test_prepared1'::regclass;
-- The insert should show the newly altered column but not the DDL.
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test that we decode correctly while an uncommitted prepared xact
-- with ddl exists.
@ -47,14 +47,14 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
-- the ALTER will stop us inserting into the other one.
--
INSERT INTO test_prepared2 VALUES (5);
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
COMMIT PREPARED 'test_prepared#3';
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- make sure stuff still works
INSERT INTO test_prepared1 VALUES (6);
INSERT INTO test_prepared2 VALUES (7);
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Check 'CLUSTER' (as operation that hold exclusive lock) doesn't block
-- logical decoding.
@ -70,11 +70,11 @@ WHERE locktype = 'relation'
AND relation = 'test_prepared1'::regclass;
-- The above CLUSTER command shouldn't cause a timeout on 2pc decoding.
SET statement_timeout = '180s';
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
RESET statement_timeout;
COMMIT PREPARED 'test_prepared_lock';
-- consume the commit
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test savepoints and sub-xacts. Creating savepoints will create
-- sub-xacts implicitly.
@ -86,26 +86,26 @@ INSERT INTO test_prepared_savepoint VALUES (2);
ROLLBACK TO SAVEPOINT test_savepoint;
PREPARE TRANSACTION 'test_prepared_savepoint';
-- should show only 1, not 2
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
COMMIT PREPARED 'test_prepared_savepoint';
-- consume the commit
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test that a GID containing "_nodecode" gets decoded at commit prepared time.
BEGIN;
INSERT INTO test_prepared1 VALUES (20);
PREPARE TRANSACTION 'test_prepared_nodecode';
-- should show nothing
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
COMMIT PREPARED 'test_prepared_nodecode';
-- should be decoded now
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
-- Test 8:
-- cleanup and make sure results are also empty
DROP TABLE test_prepared1;
DROP TABLE test_prepared2;
-- show results. There should be nothing to show
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
SELECT pg_drop_replication_slot('regression_slot');

10
contrib/test_decoding/sql/twophase_stream.sql
View File

@ -1,7 +1,7 @@
-- Test streaming of two-phase commits
SET synchronous_commit = on;
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding', false, true);
CREATE TABLE stream_test(data text);
@ -18,11 +18,11 @@ ROLLBACK TO s1;
INSERT INTO stream_test SELECT repeat('a', 10) || g.i FROM generate_series(1, 20) g(i);
PREPARE TRANSACTION 'test1';
-- should show the inserts after a ROLLBACK
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
COMMIT PREPARED 'test1';
--should show the COMMIT PREPARED and the other changes in the transaction
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
-- streaming test with sub-transaction and PREPARE/COMMIT PREPARED but with
-- filtered gid. gids with '_nodecode' will not be decoded at prepare time.
@ -35,11 +35,11 @@ ROLLBACK to s1;
INSERT INTO stream_test SELECT repeat('a', 10) || g.i FROM generate_series(1, 20) g(i);
PREPARE TRANSACTION 'test1_nodecode';
-- should NOT show inserts after a ROLLBACK
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
COMMIT PREPARED 'test1_nodecode';
-- should show the inserts but not show a COMMIT PREPARED but a COMMIT
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-phase-commit', '1', 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'include-xids', '0', 'skip-empty-xacts', '1', 'stream-changes', '1');
DROP TABLE stream_test;
SELECT pg_drop_replication_slot('regression_slot');