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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
contrib/test_decoding/expected/twophase.out
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);
?column?
----------
init
@ -15,14 +15,14 @@ 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');
data
------
(0 rows)
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');
data
----------------------------------------------------
BEGIN
@ -32,7 +32,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
(4 rows)
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');
data
-----------------------------------
COMMIT PREPARED 'test_prepared#1'
@ -42,7 +42,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
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');
data
----------------------------------------------------
BEGIN
@ -51,7 +51,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
(3 rows)
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');
data
-------------------------------------
ROLLBACK PREPARED 'test_prepared#2'
@ -74,7 +74,7 @@ WHERE locktype = 'relation'
(2 rows)
-- 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');
data
-------------------------------------------------------------------------
BEGIN
@ -89,7 +89,7 @@ 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');
data
----------------------------------------------------
BEGIN
@ -98,7 +98,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
(3 rows)
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');
data
-----------------------------------
COMMIT PREPARED 'test_prepared#3'
@ -107,7 +107,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
-- 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');
data
--------------------------------------------------------------------
BEGIN
@ -138,7 +138,7 @@ WHERE locktype = 'relation'
-- 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');
data
---------------------------------------------------------------------------
BEGIN
@ -150,7 +150,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
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');
data
--------------------------------------
COMMIT PREPARED 'test_prepared_lock'
@ -166,7 +166,7 @@ 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');
data
------------------------------------------------------------
BEGIN
@ -176,7 +176,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
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');
data
-------------------------------------------
COMMIT PREPARED 'test_prepared_savepoint'
@ -187,14 +187,14 @@ 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');
data
------
(0 rows)
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');
data
---------------------------------------------------------------------
BEGIN
@ -207,7 +207,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two
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');
data
------
(0 rows)

6
contrib/test_decoding/expected/twophase_snapshot.out
View File

@ -6,7 +6,7 @@ step s2txid: SELECT pg_current_xact_id() IS NULL;
?column?
f
step s1init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding'); <waiting ...>
step s1init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding', false, true); <waiting ...>
step s3b: BEGIN;
step s3txid: SELECT pg_current_xact_id() IS NULL;
?column?
@ -22,14 +22,14 @@ step s1init: <... completed>
init
step s1insert: INSERT INTO do_write DEFAULT VALUES;
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1', 'two-phase-commit', '1');
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1');
data
BEGIN
table public.do_write: INSERT: id[integer]:2
COMMIT
step s2cp: COMMIT PREPARED 'test1';
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1', 'two-phase-commit', '1');
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1');
data
BEGIN

10
contrib/test_decoding/expected/twophase_stream.out
View File

@ -1,6 +1,6 @@
-- 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);
?column?
----------
init
@ -28,7 +28,7 @@ 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');
data
----------------------------------------------------------
streaming message: transactional: 1 prefix: test, sz: 50
@ -59,7 +59,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-
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');
data
-------------------------
COMMIT PREPARED 'test1'
@ -81,7 +81,7 @@ 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');
data
----------------------------------------------------------
streaming message: transactional: 1 prefix: test, sz: 50
@ -89,7 +89,7 @@ SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL,NULL, 'two-
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');
data
-------------------------------------------------------------
BEGIN

4
contrib/test_decoding/specs/twophase_snapshot.spec
View File

@ -15,8 +15,8 @@ teardown
session "s1"
setup { SET synchronous_commit=on; }
step "s1init" {SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding');}
step "s1start" {SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1', 'two-phase-commit', '1');}
step "s1init" {SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding', false, true);}
step "s1start" {SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false', 'skip-empty-xacts', '1');}
step "s1insert" { INSERT INTO do_write DEFAULT VALUES; }
session "s2"

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');

12
contrib/test_decoding/test_decoding.c
View File

@ -164,7 +164,6 @@ pg_decode_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
ListCell *option;
TestDecodingData *data;
bool enable_streaming = false;
bool enable_twophase = false;
data = palloc0(sizeof(TestDecodingData));
data->context = AllocSetContextCreate(ctx->context,
@ -265,16 +264,6 @@ pg_decode_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
errmsg("could not parse value \"%s\" for parameter \"%s\"",
strVal(elem->arg), elem->defname)));
}
else if (strcmp(elem->defname, "two-phase-commit") == 0)
{
if (elem->arg == NULL)
continue;
else if (!parse_bool(strVal(elem->arg), &enable_twophase))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not parse value \"%s\" for parameter \"%s\"",
strVal(elem->arg), elem->defname)));
}
else
{
ereport(ERROR,
@ -286,7 +275,6 @@ pg_decode_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
}
ctx->streaming &= enable_streaming;
ctx->twophase &= enable_twophase;
}
/* cleanup this plugin's resources */

10
doc/src/sgml/catalogs.sgml
View File

@ -11529,6 +11529,16 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
is <literal>-1</literal>.
</para></entry>
</row>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>two_phase</structfield> <type>bool</type>
</para>
<para>
True if the slot is enabled for decoding prepared transactions. Always
false for physical slots.
</para></entry>
</row>
</tbody>
</tgroup>
</table>

10
doc/src/sgml/func.sgml
View File

@ -25559,7 +25559,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
<indexterm>
<primary>pg_create_logical_replication_slot</primary>
</indexterm>
<function>pg_create_logical_replication_slot</function> ( <parameter>slot_name</parameter> <type>name</type>, <parameter>plugin</parameter> <type>name</type> <optional>, <parameter>temporary</parameter> <type>boolean</type> </optional> )
<function>pg_create_logical_replication_slot</function> ( <parameter>slot_name</parameter> <type>name</type>, <parameter>plugin</parameter> <type>name</type> <optional>, <parameter>temporary</parameter> <type>boolean</type>, <parameter>two_phase</parameter> <type>boolean</type> </optional> )
<returnvalue>record</returnvalue>
( <parameter>slot_name</parameter> <type>name</type>,
<parameter>lsn</parameter> <type>pg_lsn</type> )
@ -25571,9 +25571,11 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
parameter, <parameter>temporary</parameter>, when set to true, specifies that
the slot should not be permanently stored to disk and is only meant
for use by the current session. Temporary slots are also
released upon any error. A call to this function has the same
effect as the replication protocol command
<literal>CREATE_REPLICATION_SLOT ... LOGICAL</literal>.
released upon any error. The optional fourth parameter,
<parameter>two_phase</parameter>, when set to true, specifies
that the decoding of prepared transactions is enabled for this
slot. A call to this function has the same effect as the replication
protocol command <literal>CREATE_REPLICATION_SLOT ... LOGICAL</literal>.
</para></entry>
</row>

19
doc/src/sgml/logicaldecoding.sgml
View File

@ -55,7 +55,7 @@
<programlisting>
postgres=# -- Create a slot named 'regression_slot' using the output plugin 'test_decoding'
postgres=# SELECT * FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
postgres=# SELECT * FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding', false, true);
slot_name | lsn
-----------------+-----------
regression_slot | 0/16B1970
@ -169,17 +169,18 @@ $ pg_recvlogical -d postgres --slot=test --drop-slot
<para>
The following example shows SQL interface that can be used to decode prepared
transactions. Before you use two-phase commit commands, you must set
<varname>max_prepared_transactions</varname> to at least 1. You must also set
the option 'two-phase-commit' to 1 while calling
<function>pg_logical_slot_get_changes</function>. Note that we will stream
the entire transaction after the commit if it is not already decoded.
<varname>max_prepared_transactions</varname> to at least 1. You must also have
set the two-phase parameter as 'true' while creating the slot using
<function>pg_create_logical_replication_slot</function>
Note that we will stream the entire transaction after the commit if it
is not already decoded.
</para>
<programlisting>
postgres=# BEGIN;
postgres=*# INSERT INTO data(data) VALUES('5');
postgres=*# PREPARE TRANSACTION 'test_prepared1';
postgres=# SELECT * FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1');
postgres=# SELECT * FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL);
lsn | xid | data
-----------+-----+---------------------------------------------------------
0/1689DC0 | 529 | BEGIN 529
@ -188,7 +189,7 @@ postgres=# SELECT * FROM pg_logical_slot_get_changes('regression_slot', NULL, NU
(3 rows)
postgres=# COMMIT PREPARED 'test_prepared1';
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1');
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL);
lsn | xid | data
-----------+-----+--------------------------------------------
0/168A060 | 529 | COMMIT PREPARED 'test_prepared1', txid 529
@ -198,7 +199,7 @@ postgres=#-- you can also rollback a prepared transaction
postgres=# BEGIN;
postgres=*# INSERT INTO data(data) VALUES('6');
postgres=*# PREPARE TRANSACTION 'test_prepared2';
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1');
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL);
lsn | xid | data
-----------+-----+---------------------------------------------------------
0/168A180 | 530 | BEGIN 530
@ -207,7 +208,7 @@ postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NU
(3 rows)
postgres=# ROLLBACK PREPARED 'test_prepared2';
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'two-phase-commit', '1');
postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NULL);
lsn | xid | data
-----------+-----+----------------------------------------------
0/168A4B8 | 530 | ROLLBACK PREPARED 'test_prepared2', txid 530

4
src/backend/catalog/system_views.sql
View File

@ -894,7 +894,8 @@ CREATE VIEW pg_replication_slots AS
L.restart_lsn,
L.confirmed_flush_lsn,
L.wal_status,
L.safe_wal_size
L.safe_wal_size,
L.two_phase
FROM pg_get_replication_slots() AS L
LEFT JOIN pg_database D ON (L.datoid = D.oid);
@ -1318,6 +1319,7 @@ AS 'pg_create_physical_replication_slot';
CREATE OR REPLACE FUNCTION pg_create_logical_replication_slot(
IN slot_name name, IN plugin name,
IN temporary boolean DEFAULT false,
IN twophase boolean DEFAULT false,
OUT slot_name name, OUT lsn pg_lsn)
RETURNS RECORD
LANGUAGE INTERNAL

12
src/backend/replication/logical/logical.c
View File

@ -431,6 +431,12 @@ CreateInitDecodingContext(const char *plugin,
startup_cb_wrapper(ctx, &ctx->options, true);
MemoryContextSwitchTo(old_context);
/*
* We allow decoding of prepared transactions iff the two_phase option is
* enabled at the time of slot creation.
*/
ctx->twophase &= MyReplicationSlot->data.two_phase;
ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
return ctx;
@ -531,6 +537,12 @@ CreateDecodingContext(XLogRecPtr start_lsn,
startup_cb_wrapper(ctx, &ctx->options, false);
MemoryContextSwitchTo(old_context);
/*
* We allow decoding of prepared transactions iff the two_phase option is
* enabled at the time of slot creation.
*/
ctx->twophase &= MyReplicationSlot->data.two_phase;
ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
ereport(LOG,

10
src/backend/replication/slot.c
View File

@ -216,10 +216,17 @@ ReplicationSlotValidateName(const char *name, int elevel)
* name: Name of the slot
* db_specific: logical decoding is db specific; if the slot is going to
* be used for that pass true, otherwise false.
* two_phase: Allows decoding of prepared transactions. We allow this option
* to be enabled only at the slot creation time. If we allow this option
* to be changed during decoding then it is quite possible that we skip
* prepare first time because this option was not enabled. 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.
*/
void
ReplicationSlotCreate(const char *name, bool db_specific,
ReplicationSlotPersistency persistency)
ReplicationSlotPersistency persistency, bool two_phase)
{
ReplicationSlot *slot = NULL;
int i;
@ -277,6 +284,7 @@ ReplicationSlotCreate(const char *name, bool db_specific,
namestrcpy(&slot->data.name, name);
slot->data.database = db_specific ? MyDatabaseId : InvalidOid;
slot->data.persistency = persistency;
slot->data.two_phase = two_phase;
/* and then data only present in shared memory */
slot->just_dirtied = false;

14
src/backend/replication/slotfuncs.c
View File

@ -50,7 +50,7 @@ create_physical_replication_slot(char *name, bool immediately_reserve,
/* acquire replication slot, this will check for conflicting names */
ReplicationSlotCreate(name, false,
temporary ? RS_TEMPORARY : RS_PERSISTENT);
temporary ? RS_TEMPORARY : RS_PERSISTENT, false);
if (immediately_reserve)
{
@ -124,7 +124,8 @@ pg_create_physical_replication_slot(PG_FUNCTION_ARGS)
*/
static void
create_logical_replication_slot(char *name, char *plugin,
bool temporary, XLogRecPtr restart_lsn,
bool temporary, bool two_phase,
XLogRecPtr restart_lsn,
bool find_startpoint)
{
LogicalDecodingContext *ctx = NULL;
@ -140,7 +141,7 @@ create_logical_replication_slot(char *name, char *plugin,
* error as well.
*/
ReplicationSlotCreate(name, true,
temporary ? RS_TEMPORARY : RS_EPHEMERAL);
temporary ? RS_TEMPORARY : RS_EPHEMERAL, two_phase);
/*
* Create logical decoding context to find start point or, if we don't
@ -177,6 +178,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS)
Name name = PG_GETARG_NAME(0);
Name plugin = PG_GETARG_NAME(1);
bool temporary = PG_GETARG_BOOL(2);
bool two_phase = PG_GETARG_BOOL(3);
Datum result;
TupleDesc tupdesc;
HeapTuple tuple;
@ -193,6 +195,7 @@ pg_create_logical_replication_slot(PG_FUNCTION_ARGS)
create_logical_replication_slot(NameStr(*name),
NameStr(*plugin),
temporary,
two_phase,
InvalidXLogRecPtr,
true);
@ -236,7 +239,7 @@ pg_drop_replication_slot(PG_FUNCTION_ARGS)
Datum
pg_get_replication_slots(PG_FUNCTION_ARGS)
{
#define PG_GET_REPLICATION_SLOTS_COLS 13
#define PG_GET_REPLICATION_SLOTS_COLS 14
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
@ -432,6 +435,8 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
values[i++] = Int64GetDatum(failLSN - currlsn);
}
values[i++] = BoolGetDatum(slot_contents.data.two_phase);
Assert(i == PG_GET_REPLICATION_SLOTS_COLS);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
@ -796,6 +801,7 @@ copy_replication_slot(FunctionCallInfo fcinfo, bool logical_slot)
create_logical_replication_slot(NameStr(*dst_name),
plugin,
temporary,
false,
src_restart_lsn,
false);
}

6
src/backend/replication/walsender.c
View File

@ -938,7 +938,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
if (cmd->kind == REPLICATION_KIND_PHYSICAL)
{
ReplicationSlotCreate(cmd->slotname, false,
cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT);
cmd->temporary ? RS_TEMPORARY : RS_PERSISTENT,
false);
}
else
{
@ -952,7 +953,8 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
* they get dropped on error as well.
*/
ReplicationSlotCreate(cmd->slotname, true,
cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL);
cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL,
cmd->two_phase);
}
if (cmd->kind == REPLICATION_KIND_LOGICAL)

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202102191
#define CATALOG_VERSION_NO 202103031
#endif

14
src/include/catalog/pg_proc.dat
View File

@ -10496,16 +10496,16 @@
proname => 'pg_get_replication_slots', prorows => '10', proisstrict => 'f',
proretset => 't', provolatile => 's', prorettype => 'record',
proargtypes => '',
proallargtypes => '{name,name,text,oid,bool,bool,int4,xid,xid,pg_lsn,pg_lsn,text,int8}',
proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o}',
proargnames => '{slot_name,plugin,slot_type,datoid,temporary,active,active_pid,xmin,catalog_xmin,restart_lsn,confirmed_flush_lsn,wal_status,safe_wal_size}',
proallargtypes => '{name,name,text,oid,bool,bool,int4,xid,xid,pg_lsn,pg_lsn,text,int8,bool}',
proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
proargnames => '{slot_name,plugin,slot_type,datoid,temporary,active,active_pid,xmin,catalog_xmin,restart_lsn,confirmed_flush_lsn,wal_status,safe_wal_size,two_phase}',
prosrc => 'pg_get_replication_slots' },
{ oid => '3786', descr => 'set up a logical replication slot',
proname => 'pg_create_logical_replication_slot', provolatile => 'v',
proparallel => 'u', prorettype => 'record', proargtypes => 'name name bool',
proallargtypes => '{name,name,bool,name,pg_lsn}',
proargmodes => '{i,i,i,o,o}',
proargnames => '{slot_name,plugin,temporary,slot_name,lsn}',
proparallel => 'u', prorettype => 'record', proargtypes => 'name name bool bool',
proallargtypes => '{name,name,bool,bool,name,pg_lsn}',
proargmodes => '{i,i,i,i,o,o}',
proargnames => '{slot_name,plugin,temporary,twophase,slot_name,lsn}',
prosrc => 'pg_create_logical_replication_slot' },
{ oid => '4222',
descr => 'copy a logical replication slot, changing temporality and plugin',

1
src/include/nodes/replnodes.h
View File

@ -56,6 +56,7 @@ typedef struct CreateReplicationSlotCmd
ReplicationKind kind;
char *plugin;
bool temporary;
bool two_phase;
List *options;
} CreateReplicationSlotCmd;

7
src/include/replication/slot.h
View File

@ -98,6 +98,11 @@ typedef struct ReplicationSlotPersistentData
*/
XLogRecPtr initial_consistent_point;
/*
* Allow decoding of prepared transactions?
*/
bool two_phase;
/* plugin name */
NameData plugin;
} ReplicationSlotPersistentData;
@ -199,7 +204,7 @@ extern void ReplicationSlotsShmemInit(void);
/* management of individual slots */
extern void ReplicationSlotCreate(const char *name, bool db_specific,
ReplicationSlotPersistency p);
ReplicationSlotPersistency p, bool two_phase);
extern void ReplicationSlotPersist(void);
extern void ReplicationSlotDrop(const char *name, bool nowait);

5
src/test/regress/expected/rules.out
View File

@ -1477,8 +1477,9 @@ pg_replication_slots| SELECT l.slot_name,
l.restart_lsn,
l.confirmed_flush_lsn,
l.wal_status,
l.safe_wal_size
FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid, temporary, active, active_pid, xmin, catalog_xmin, restart_lsn, confirmed_flush_lsn, wal_status, safe_wal_size)
l.safe_wal_size,
l.two_phase
FROM (pg_get_replication_slots() l(slot_name, plugin, slot_type, datoid, temporary, active, active_pid, xmin, catalog_xmin, restart_lsn, confirmed_flush_lsn, wal_status, safe_wal_size, two_phase)
LEFT JOIN pg_database d ON ((l.datoid = d.oid)));
pg_roles| SELECT pg_authid.rolname,
pg_authid.rolsuper,