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MDEV-38636 @@sql_slave_skip_counter resets to 1 when skipping events by @@gtid_ignore_duplicates #4593

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MDEV-38636 @@sql_slave_skip_counter resets to 1 when skipping events by @@gtid_ignore_duplicates #4593

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4 changes: 4 additions & 0 deletions mysql-test/suite/multi_source/gtid_ignore_duplicates_skip_counter.cnf
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
!include my.cnf

[mysqld.2]
log-slave-updates
46 changes: 46 additions & 0 deletions mysql-test/suite/multi_source/gtid_ignore_duplicates_skip_counter.result
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@@ -0,0 +1,46 @@
include/rpl_init.inc [topology=1->2, 1->3]
# Set up
CREATE TABLE t (a INT);
include/save_master_pos.inc
include/save_master_gtid.inc
connection server_2;
START SLAVE;
include/sync_with_master_gtid.inc
connection server_3;
SET @save_gtid_ignore_duplicates= @@GLOBAL.gtid_ignore_duplicates;
SET @@GLOBAL.gtid_ignore_duplicates= ON;
START SLAVE IO_THREAD;
include/sync_io_with_master.inc
CHANGE MASTER 'bridge' TO
master_host='127.0.0.1', master_port=SERVER_MYPORT_2, master_user='root';
SET @@SESSION.default_master_connection= 'bridge';
include/start_slave.inc
include/sync_with_master_gtid.inc
include/stop_slave.inc
SET @@SESSION.default_master_connection= '';
RESET SLAVE 'bridge' ALL;
# Test
SET @@GLOBAL.sql_slave_skip_counter= 100;
START SLAVE SQL_THREAD;
include/wait_for_slave_param.inc [Relay_Master_Log_File]
include/wait_for_slave_param.inc [Exec_Master_Log_Pos]
SELECT @@sql_slave_skip_counter;
@@sql_slave_skip_counter
100
Skip_Counter = '100'
connection server_1;
DROP TABLE t;
include/save_master_gtid.inc
connection server_2;
include/sync_with_master_gtid.inc
connection server_3;
include/sync_with_master_gtid.inc
SHOW TABLES;
Tables_in_test
t
# Tear down
include/stop_slave.inc
SET @@GLOBAL.sql_slave_skip_counter= 0;
SET @@GLOBAL.gtid_ignore_duplicates= @save_gtid_ignore_duplicates;
SET STATEMENT sql_log_bin=0 FOR DROP TABLE t;
include/rpl_end.inc
70 changes: 70 additions & 0 deletions mysql-test/suite/multi_source/gtid_ignore_duplicates_skip_counter.test
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@@ -0,0 +1,70 @@
# Test combining `@@gtid_ignore_duplicates` and `@@sql_slave_skip_counter`
#
# Reference: MDEV-38636 `@@sql_slave_skip_counter`
# resets to 1 when skipping events by `@@gtid_ignore_duplicates`

--let $rpl_topology= 1->2, 1->3
--let $rpl_skip_start_slave= 1
--source include/rpl_init.inc


--echo # Set up

# Create some events to trigger `@@gtid_ignore_duplicates` with
CREATE TABLE t (a INT);
--source include/save_master_pos.inc
--source include/save_master_gtid.inc

--connection server_2
START SLAVE;
--source include/sync_with_master_gtid.inc

--connection server_3
SET @save_gtid_ignore_duplicates= @@GLOBAL.gtid_ignore_duplicates;
SET @@GLOBAL.gtid_ignore_duplicates= ON;

# Queue the test events without processing (which increments `@@gtid_slave_pos`)
START SLAVE IO_THREAD;
--source include/sync_io_with_master.inc

# Queue and process second copies of the events through another connection
--replace_result $SERVER_MYPORT_2 SERVER_MYPORT_2
eval CHANGE MASTER 'bridge' TO
master_host='127.0.0.1', master_port=$SERVER_MYPORT_2, master_user='root';
SET @@SESSION.default_master_connection= 'bridge';
--source include/start_slave.inc
--source include/sync_with_master_gtid.inc
--source include/stop_slave.inc
SET @@SESSION.default_master_connection= '';
RESET SLAVE 'bridge' ALL;


--echo # Test

SET @@GLOBAL.sql_slave_skip_counter= 100;
START SLAVE SQL_THREAD;
--source include/sync_with_master.inc

SELECT @@sql_slave_skip_counter;
--let $status_items= Skip_Counter
--source include/show_slave_status.inc

--connection server_1
DROP TABLE t;
--source include/save_master_gtid.inc
--connection server_2
--source include/sync_with_master_gtid.inc
--connection server_3
--source include/sync_with_master_gtid.inc
SHOW TABLES; # The counter should continue to skip the DROP TABLE.


--echo # Tear down

--source include/stop_slave.inc
SET @@GLOBAL.sql_slave_skip_counter= 0;
SET @@GLOBAL.gtid_ignore_duplicates= @save_gtid_ignore_duplicates;
SET STATEMENT sql_log_bin=0 FOR DROP TABLE t;

--let $rpl_only_running_threads= 1
--source include/rpl_end.inc
11 changes: 9 additions & 2 deletions sql/log_event_server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -660,6 +660,8 @@ Log_event::do_shall_skip(rpl_group_info *rgi)
rli->slave_skip_counter));
if ((server_id == global_system_variables.server_id &&
!(rli->replicate_same_server_id || (flags & LOG_EVENT_ACCEPT_OWN_F))) ||
rgi->gtid_ignore_duplicate_state ==
rpl_group_info::GTID_DUPLICATE_IGNORE ||
(rli->slave_skip_counter == 1 && rli->is_in_group()) ||
(flags & LOG_EVENT_SKIP_REPLICATION_F &&
opt_replicate_events_marked_for_skip != RPL_SKIP_REPLICATE))
Expand Down Expand Up @@ -2455,7 +2457,8 @@ Query_log_event::do_shall_skip(rpl_group_info *rgi)
opt_replicate_events_marked_for_skip != RPL_SKIP_REPLICATE)
DBUG_RETURN(Log_event::EVENT_SKIP_IGNORE);

if (rli->slave_skip_counter > 0)
if (rli->slave_skip_counter ||
rgi->gtid_ignore_duplicate_state == rpl_group_info::GTID_DUPLICATE_IGNORE)
{
if (is_begin())
{
Expand All @@ -2466,6 +2469,9 @@ Query_log_event::do_shall_skip(rpl_group_info *rgi)
if (is_commit() || is_rollback())
{
thd->variables.option_bits&= ~(OPTION_BEGIN | OPTION_GTID_BEGIN);
if (rgi->gtid_ignore_duplicate_state ==
rpl_group_info::GTID_DUPLICATE_IGNORE)
DBUG_RETURN(Log_event::EVENT_SKIP_IGNORE);
DBUG_RETURN(Log_event::EVENT_SKIP_COUNT);
}
}
Expand Down Expand Up @@ -3993,7 +3999,8 @@ Gtid_log_event::do_shall_skip(rpl_group_info *rgi)
opt_replicate_events_marked_for_skip != RPL_SKIP_REPLICATE)
return Log_event::EVENT_SKIP_IGNORE;

if (rli->slave_skip_counter > 0)
if (rli->slave_skip_counter ||
rgi->gtid_ignore_duplicate_state == rpl_group_info::GTID_DUPLICATE_IGNORE)
{
if (!(flags2 & FL_STANDALONE))
{
Expand Down
7 changes: 0 additions & 7 deletions sql/slave.cc
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@ParadoxV5 ParadoxV5 Jan 27, 2026 •
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This section is after the block where this driver SQL thread dismisses queues events to its workers.

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@ParadoxV5 ParadoxV5 Jan 28, 2026

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We might be able to remove the @@gtid_ignore_duplicates code on the Parallel side as well now, but I don’t dare, and so leave it to MDEV-30458 Consolidate Serial Replica to Parallel Replica with 1 Worker Thread.

Original file line number Diff line number Diff line change
Expand Up @@ -4540,13 +4540,6 @@ static int exec_relay_log_event(THD* thd, Relay_log_info* rli,
#endif /* WITH_WSREP */
DBUG_RETURN(1);
}
/*
If we need to skip this event group (because the GTID was already
applied), then do it using the code for slave_skip_counter, which
is able to handle skipping until the end of the event group.
*/
if (!res)
rli->slave_skip_counter= 1;
}
}

Expand Down