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Code Activity

MDEV-33465: an option to enable semisync recovery

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The current semi-sync binlog fail-over recovery process uses
rpl_semi_sync_slave_enabled==TRUE as its condition to truncate a
primary server’s binlog, as it is anticipating the server to re-join
a replication topology as a replica. However, for servers configured
with both rpl_semi_sync_master_enabled=1 and
rpl_semi_sync_slave_enabled=1, if a primary is just re-started (i.e.
retaining its role as master), it can truncate its binlog to drop
transactions which its replica(s) has already received and executed.
If this happens, when the replica reconnects, its gtid_slave_pos can
be ahead of the recovered primary’s gtid_binlog_pos, resulting in an
error state where the replica’s state is ahead of the primary’s.

This patch changes the condition for semi-sync recovery to truncate
the binlog to instead use the configuration variable
--init-rpl-role, when set to SLAVE. This allows for both
rpl_semi_sync_master_enabled and rpl_semi_sync_slave_enabled to be
set for a primary that is restarted, and no transactions will be
lost, so long as --init-rpl-role is not set to SLAVE.

Reviewed By:
============
Sergei Golubchik <serg@mariadb.com>
This commit is contained in:
Brandon Nesterenko
2024-02-29 11:51:09 -07:00
committed by Brandon Nesterenko
parent e40d232ad6
commit eb4458e993
12 changed files with 24 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
mysql-test/suite/binlog/t/binlog_truncate_multi_engine.test
View File

@@ -28,7 +28,7 @@ CREATE TABLE t2 (a INT PRIMARY KEY, b MEDIUMTEXT) ENGINE=rocksdb;
# The transaction is killed along with the server after that.
--let $shutdown_timeout=0
--let $debug_sync_action = "commit_after_release_LOCK_log SIGNAL con1_ready WAIT_FOR signal_no_signal"
--let $restart_parameters = --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
--let $restart_parameters = --init-rpl-role=SLAVE --sync-binlog=1
--let $test_outcome= 1 row should be present in both tables; binlog is truncated; number of binlogs at reconnect - 3
--source binlog_truncate_multi_engine.inc
--echo Proof of the truncated binlog file is readable (two transactions must be seen):
@@ -41,7 +41,7 @@ CREATE TABLE t2 (a INT PRIMARY KEY, b MEDIUMTEXT) ENGINE=rocksdb;
--let $debug_sync_action = ""
# Both debug_sync and debug-dbug are required to make sure Engines remember the commit state
# debug_sync alone will not help.
--let $restart_parameters = --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
--let $restart_parameters = --init-rpl-role=SLAVE --sync-binlog=1
--let $test_outcome= 2 rows should be present in both tables; no binlog truncation; one extra binlog file compare with A; number of binlogs at reconnect - 4
--source binlog_truncate_multi_engine.inc
@@ -50,7 +50,7 @@ CREATE TABLE t2 (a INT PRIMARY KEY, b MEDIUMTEXT) ENGINE=rocksdb;
--let $debug_sync_action = "commit_after_run_commit_ordered SIGNAL con1_ready"
# Hold off after both engines have committed. The server is shut down.
--let $shutdown_timeout=
--let $restart_parameters = --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
--let $restart_parameters = --init-rpl-role=SLAVE --sync-binlog=1
--let $test_outcome= 2 rows should be present in both tables; no binlog truncation; the same # of binlog files as in B; number of binlogs at reconnect - 4
--source binlog_truncate_multi_engine.inc