Test rpl.rpl_backup_locks_mts is unstable

[Laurynas Biveinis]

On 5.6 trunk:

rpl.rpl_backup_locks_mts 'row' w1 [ fail ]
...
**** SHOW PROCESSLIST on slave ****
SHOW PROCESSLIST;
Id User Host db Command Time State Info Rows_sent Rows_examined
2 root localhost:34887 test Sleep 31 NULL 1 0
3 root localhost:34888 test Sleep 31 NULL 1 0
6 root localhost:34895 test Query 0 init SHOW PROCESSLIST 0 0
7 root localhost:34896 test Sleep 31 NULL 1 0
8 system user NULL Connect 31 Waiting for master to send event NULL 0 0
9 system user NULL Connect 31 Waiting for binlog lock NULL 0 0
10 system user NULL Connect 31 Waiting for an event from Coordinator NULL 0 0
11 system user NULL Connect 31 Waiting for an event from Coordinator NULL 0 0
...

The testcase expects the slave parallel worker threads to wait for the binlog lock, but sometimes it is the SQL coordinator slave thread which waits for it.

[Laurynas Biveinis (laurynas-biveinis)]

(lldb) bt
* thread #25: tid = 0x0018, 0x00007fff95a47db6 libsystem_kernel.dylib`__psynch_cvwait + 10, stop reason = signal SIGSTOP
  * frame #0: 0x00007fff95a47db6 libsystem_kernel.dylib`__psynch_cvwait + 10
    frame #1: 0x00007fff986f4728 libsystem_pthread.dylib`_pthread_cond_wait + 767
    frame #2: 0x0000000109377fb5 mysqld-debug`safe_cond_timedwait(cond=0x00007fb42e846848, mp=0x00007fb42e8467a8, abstime=0x0000700000a040b8, file="/Users/laurynas/percona/mysql-server/include/mysql/psi/mysql_thread.h", line=1188) + 213 at thr_mutex.c:278
    frame #3: 0x0000000108f5d064 mysqld-debug`inline_mysql_cond_timedwait(that=0x00007fb42e846848, mutex=0x00007fb42e8467a8, abstime=0x0000700000a040b8, src_file="/Users/laurynas/percona/mysql-server/sql/mdl.cc", src_line=1439) + 132 at mysql_thread.h:1188
    frame #4: 0x0000000108f5cf27 mysqld-debug`MDL_wait::timed_wait(this=0x00007fb42e8467a8, owner=0x00007fb42e846600, abs_timeout=0x0000700000a040b8, set_status_on_timeout=false, wait_state_name=0x0000000109aaf3d0) + 311 at mdl.cc:1438
    frame #5: 0x0000000108f5e6a7 mysqld-debug`MDL_context::acquire_lock(this=0x00007fb42e8467a8, mdl_request=0x0000700000a04190, lock_wait_timeout=31536000) + 903 at mdl.cc:2379
    frame #6: 0x0000000108f4e5d7 mysqld-debug`Global_backup_lock::acquire_protection(this=0x00007fb42e8481b0, thd=0x00007fb42e846600, duration=MDL_EXPLICIT, lock_wait_timeout=31536000) + 279 at lock.cc:1227
    frame #7: 0x000000010932bc99 mysqld-debug`Relay_log_info::inc_group_relay_log_pos(this=0x00007fb42e820000, log_pos=0, need_data_lock=true) + 393 at rpl_rli.cc:997
    frame #8: 0x000000010932d4c6 mysqld-debug`Relay_log_info::stmt_done(this=0x00007fb42e820000, event_master_log_pos=0) + 374 at rpl_rli.cc:1521
    frame #9: 0x00000001092916d6 mysqld-debug`Log_event::do_update_pos(this=0x00007fb42e007cf0, rli=0x00007fb42e820000) + 182 at log_event.cc:875
    frame #10: 0x00000001092a0714 mysqld-debug`Format_description_log_event::do_update_pos(this=0x00007fb42e007cf0, rli=0x00007fb42e820000) + 84 at log_event.cc:5834
    frame #11: 0x0000000109322d32 mysqld-debug`Log_event::update_pos(this=0x00007fb42e007cf0, rli=0x00007fb42e820000) + 50 at log_event.h:1577
    frame #12: 0x000000010930ffbf mysqld-debug`apply_event_and_update_pos(ptr_ev=0x0000700000a046f8, thd=0x00007fb42e846600, rli=0x00007fb42e820000) + 2847 at rpl_slave.cc:4143
    frame #13: 0x0000000109319c88 mysqld-debug`exec_relay_log_event(thd=0x00007fb42e846600, rli=0x00007fb42e820000) + 1352 at rpl_slave.cc:4479
    frame #14: 0x00000001093090e2 mysqld-debug`::handle_slave_sql(arg=0x00007fb42c83ca00) + 3442 at rpl_slave.cc:6408
    frame #15: 0x00000001097553dd mysqld-debug`::pfs_spawn_thread(arg=0x00007fb42e0018b0) + 333 at pfs.cc:1860
    frame #16: 0x00007fff986f399d libsystem_pthread.dylib`_pthread_body + 131
    frame #17: 0x00007fff986f391a libsystem_pthread.dylib`_pthread_start + 168
    frame #18: 0x00007fff986f1351 libsystem_pthread.dylib`thread_start + 13

[Laurynas Biveinis (laurynas-biveinis)]

     https://github.com/percona/percona-server/pull/886
     https://github.com/percona/percona-server/pull/887

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-2180