Change of user interface to be more logical and more in line with expectations
to work similar to old-style replication.
User can now explicitly choose in CHANGE MASTER whether binlog position is
taken into account (master_gtid_pos=current_pos) or not (master_gtid_pos=
slave_pos) when slave connects to master.
@@gtid_pos is replaced by three separate variables @@gtid_slave_pos (can
be set by user, replicated GTIDs only), @@gtid_binlog_pos (read only), and
@@gtid_current_pos (a combination of the two, most recent GTID within each
domain). mysql.rpl_slave_state is renamed to mysql.gtid_slave_pos to match.
This fixes MDEV-4474.
Replace CHANGE MASTER TO ... master_gtid_pos='xxx' with a new system
variable @@global.gtid_pos.
This is more logical; @@gtid_pos is global, not per-master, and it is not
affected by RESET SLAVE.
Also rename master_gtid_pos=AUTO to master_use_gtid=1, which again is more
logical.
More fixes for test failures in Buildbot:
- Do not run crashing test in Valgrind.
- FLUSH TABLES did not work to avoid errors about not closed tables when
crashing server. Suppress the messages instead.
- Rewrite multi-source test case to only start one pair of slave threads at a
time, to work-around the bug MDEV-4352.
Adjust full test suite to work with GTID.
Huge patch, mainly due to having to update .result file for all SHOW BINLOG
EVENTS and mysqlbinlog outputs, where the new GTID events pop up.
Everything was painstakingly checked to be still correct and valid .result
file updates.
Add test case demonstrating multi-source replication with GTID.
Test that we can move from being slave of two masters to be a slave
deeper down in the hierarchy (of a higher-up multi-source slave),
and vice versa.
