When the semisync slave is being stopped with STOP SLAVE just after
the master was shut down it attempts to reconnect with the master
anyway per a semisync routine. Instead of an expected error the
io-thread segfauls in mysql_real_connect() execution at
!mysql->options.extension->async_context
check trying to reach the extension's member while mysql->options.extension is
actually and correctly NULL.
Apparently not-NULL check for mysql->options.extension was missed and
it's deployed by the patch to fix this issue.
As a bonus it also tackles an assert
Thread 0x7f16c72148c0 (LWP 24639) 0x00007f16c53b3bf2 in __GI___assert_fail (assertion=0x55a686117558 "global_status_var.global_memory_used == 0", file=0x55a6861171e8 "/home/andrei/MDB/WTs/10.3-clean/sql/mysqld.cc", line=2201, function=0x55a68611fa80 <mysqld_exit(int)::__PRETTY_FUNCTION__> "void mysqld_exit(int)") at assert.c:101
in a new test of the patch. The reason of the assert was insufficient cleanup
in Repl_semi_sync_slave::kill_connection() which has a branch where a MYSQL instance
was left out unfred.
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.
This fix excludes rocksdb, spider,spider, sphinx and connect for now.
and specifically the ack receiving functionality.
Semisync is turned to be static instead of plugin so its functions
are invoked at the same points as RUN_HOOKS.
The RUN_HOOKS and the observer interface remain to be removed by later
patch.
Todo:
React on killed status by repl_semisync_master.wait_after_sync(). Currently
Repl_semi_sync_master::commit_trx does not check the killed status.
There were few bugfixes found that are present in mysql and its unclear
whether/how they are covered. Those include:
Bug#15985893: GTID SKIPPED EVENTS ON MASTER CAUSE SEMI SYNC TIME-OUTS
Bug#17932935 CALLING IS_SEMI_SYNC_SLAVE() IN EACH FUNCTION CALL
HAS BAD PERFORMANCE
Bug#20574628: SEMI-SYNC REPLICATION PERFORMANCE DEGRADES WITH A HIGH NUMBER OF THREADS
Part of MDEV-13073 AliSQL Optimize performance of semisync
Did the following renames to match other similar variables
key_ss_mutex_LOCK_binlog_ > key_LOCK_bing
key_ss_cond_COND_binlog_send_ -> key_COND_binlog_send
COND_binlog_send_ -> COND_binlog_send
LOCK_binlog_ -> LOCK_binlog
debian/mariadb-server-10.2.install does not install semisync libs.
2017-12-18 13:43:36 +02:00
Renamed from plugin/semisync/semisync_slave.cc (Browse further)
