Remove the test for MDEV-14528. This is supposed to test that parallel
replication from pre-10.0 master will update Seconds_Behind_Master. But
after MDEV-12179 the SQL thread is blocked from even beginning to fetch
events from the relay log due to FLUSH TABLES WITH READ LOCK, so the test
case is no longer testing what is was intended to. And pre-10.0 versions are
long since out of support, so does not seem worthwhile to try to rewrite the
test to work another way.
The root cause of the test failure is MDEV-34778. Briefly, depending on
exact timing during slave stop, the rli->sql_thread_caught_up flag may end
up with different value. If it ends up as "true", this causes
Seconds_Behind_Master to be 0 during next slave start; and this caused test
case timeout as the test was waiting for Seconds_Behind_Master to become
non-zero.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
This commit makes replicas crash-safe by default by changing the
Using_Gtid value to be Slave_Pos on a fresh slave start and after
RESET SLAVE is issued. If the primary server does not support GTIDs
(i.e., version < 10), the replica will fall back to Using_Gtid=No on
slave start and after RESET SLAVE.
The following additional informational messages/warnings are added:
1. When Using_Gtid is automatically changed. That is, if RESET
SLAVE reverts Using_Gtid back to Slave_Pos, or Using_Gtid is
inferred to No from a CHANGE MASTER TO given with log coordinates
without MASTER_USE_GTID.
2. If options are ignored in CHANGE MASTER TO. If CHANGE MASTER TO
is given with log coordinates, yet also specifies
MASTER_USE_GTID=Slave_Pos, a warning message is given that the log
coordinate options are ignored.
Additionally, an MTR macro has been added for RESET SLAVE,
reset_slave.inc, which provides modes/options for resetting a slave
in log coordinate or gtid modes. When in log coordinates mode, the
macro will execute CHANGE MASTER TO MASTER_USE_GTID=No after the
RESET SLAVE command. When in GTID mode, an extra parameter,
reset_slave_keep_gtid_state, can be set to reset or preserve the
value of gtid_slave_pos.
Reviewed By:
===========
Andrei Elkin <andrei.elkin@mariadb.com>
When replicated events are from Master unaware of MariaDB GTID their handling by
the Parallel slave misses Seconds_Behind_Master updating.
In the bug condition the Show-Slave-Status' field remains unchanged.
Because in such case event execution is sequential the bug
is fixed with deploying the same logics as in the explicit single-threaded mode
with is to set
Relay_log_event::last_master_timestamp
member early at the end of event reading from the relay log.
Older master has no GTID events, so such events are not available for
deciding on scheduling of event groups and so on.
With this patch, we run such events from old masters single-threaded, in the
sql driver thread.
This seems better than trying to make the parallel code handle the data from
older masters; while possible, this would require a lot of testing (as well as
possibly some extra overhead in the scheduling of events), which hardly seems
worthwhile.
