Move combining slave and gtid binlog state into a separate function.
Make SHOW ALL SLAVES STATUS use the same function, so it shows the
same value used by slave connect.
Add a test case.
Fix yet another race in the rpl_gtid_startpos test case.
Implement include/wait_for_purge.inc to purge binary logs; we need to
retry the purge multiple times until it succeeds in removing all the logs
we want, as binlog dump threads can be slow to stop on loaded machines and
hold back purge of logs that are still referenced by the thread.
When slave requested to start at some GTID, and that GTID was the very
last event (within its replication domain) in some binlog file, we did
not allow the binlog dump thread on the master to start from the
beginning of a following binlog file. This is a problem, since the
binlog file containing the GTID is likely to be purged if the
replication domain is unused for long.
With this fix, if the Gtid list event at the start of a binlog file
contains exactly the GTID requested by the slave, we allow to start
the binlog dump thread from this file, taking care not to skip any
events from that domain in the file.
Fix MDEV-4329. When user does CHANGE MASTER TO
MASTER_GTID_POS='<explicit GTID state>', we check that this state
does not conflict with the binlog. But the code forgot to give an
error in the case where a domain was completely missing from the
requested position (eg. MASTER_GTID_POS='').
Fix MDEV-4275 - I/O thread restart duplicates events in the relay log.
The first time we connect to master after CHANGE MASTER or restart, we connect
from the GTID position. But then subsequent reconnects or IO thread restarts
reconnect with the old-style file/offset binlog pos from where it left off at
last disconnect. This is necessary to avoid duplicate events in the relay
logs, as there is nothing that synchronises the SQL thread update of GTID
state (multiple threads in case of multi-source) with IO thread reconnects.
Test cases.
Some small cleanups and fixes.
Fix things so that a master can switch with MASTER_GTID_POS=AUTO to a slave
that was previously running with log_slave_updates=0, by looking into the
slave replication state on the master when the slave requests something not
present in the binlog.
Be a bit more strict about what position the slave can ask for, to avoid some
easy-to-hit misconfiguration errors.
Start over with seq_no counter when RESET MASTER.
Fix that CHANGE MASTER ... MASTER_GTID_POS="" works to start from the very
beginning of the binary log (with test case).
Fix that not finding the requested GTID position in master binlog results in
fatal error, not endless connect retry.
