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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
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10
mysql-test/suite/binlog/r/binlog_truncate_multi_engine.result
View File

@@ -31,9 +31,9 @@ Log_name File_size
master-bin.000001 #
master-bin.000002 #
master-bin.000003 #
# restart the server with --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
# restart the server with --init-rpl-role=SLAVE --sync-binlog=1
# the server is restarted
# restart: --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
# restart: --init-rpl-role=SLAVE --sync-binlog=1
connection default;
#
# *** Summary: 1 row should be present in both tables; binlog is truncated; number of binlogs at reconnect - 3:
@@ -98,7 +98,7 @@ INSERT INTO t2 VALUES (2, REPEAT("x", 4100));
INSERT INTO t1 VALUES (2, REPEAT("x", 4100));
COMMIT;
connection default;
# restart: --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
# restart: --init-rpl-role=SLAVE --sync-binlog=1
connection default;
#
# *** Summary: 2 rows should be present in both tables; no binlog truncation; one extra binlog file compare with A; number of binlogs at reconnect - 4:
@@ -155,9 +155,9 @@ Log_name File_size
master-bin.000001 #
master-bin.000002 #
master-bin.000003 #
# restart the server with --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
# restart the server with --init-rpl-role=SLAVE --sync-binlog=1
# the server is restarted
# restart: --rpl-semi-sync-slave-enabled=1 --sync-binlog=1
# restart: --init-rpl-role=SLAVE --sync-binlog=1
connection default;
#
# *** Summary: 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: