MDEV-10653: Fix segfault in SHOW MASTER STATUS with NULL inuse_relaylog
The previous patch for MDEV-10653 changes the rpl_parallel::workers_idle()
function to use Relay_log_info::last_inuse_relaylog to check for idle
workers. But the code was missing a NULL check. Also, there was one place
during SQL slave thread start which was missing mutex synchronisation when
updating inuse_relaylog.
Signed-off-by: Kristian Nielsen <email address hidden>
The error-injection inject_mdev8031 simulates a deadlock kill in a specific
place, by setting killed_for_retry to RETRY_KILL_KILLED directly. If a real
deadlock kill triggers at the same time, it is possible for the thread to
complete its transaction retry and set rgi_slave to NULL before the real
readlock kill can complete in the background. This will cause a segfault
due to null-pointer access.
Fix by changing the error injection to do a real background deadlock kill,
which ensures that the thread will wait for any pending background kills to
complete.
Signed-off-by: Kristian Nielsen <email address hidden>
MDEV-33009 Server hangs for a long time with innodb_undo_log_truncate=ON
trx_purge_truncate_history(): Release buf_pool.flush_list_mutex
and 'dummily' acquire and release buf_pool.mutex before starting
a rescan of buf_pool.flush_list, to ensure that
the buf_flush_page_cleaner thread (which may be holding buf_pool.mutex)
will be able to proceed.
This fixes up commit 5dbe7a8c9aa88b7ed17311c2f1df651c9da7783b (MDEV-32757).
Tested by: Axel Schwenke (on Ubuntu 18.04 and Ubuntu 20.04)
Reviewed by: Vladislav Lesin
