Problem was caused by MDEV-31413 commit 277968aa where
mysql.gtid_slave_pos table was replicated by Galera.
However, as not all nodes in Galera cluster are replica
nodes, rows were not deleted from table.
In this fix this is corrected so that mysql.gtid_slave_pos
table is not replicated by Galera. Instead when Galera
node receives GTID event and wsrep_gtid_mode=1, this event
is stored to mysql.gtid_slave_pos table.
Added test case galera_2primary_replica for 2 async
primaries replicating to galera cluster.
Added test case galera_circular_replication where
async primary replicates to galera cluster and
one of the galera cluster nodes is master
to async replica.
Modified test case galera_restart_replica to monitor
gtid positions and rows in mysql.gtid_pos_table.
There was two related problems:
(1) Galera node that is defined as a slave to async MariaDB
master at restart might do SST (state stransfer) and
part of that it will copy mysql.gtid_slave_pos table.
Problem is that updates on that table are not replicated
on a cluster. Therefore, table from donor that is not
slave is copied and joiner looses gtid position it was
and start executing events from wrong position of the binlog.
This incorrect position could break replication and
causes node to be dropped and requiring user action.
(2) Slave sql thread might start executing events before
galera is ready (wsrep_ready=ON) and that could also
cause node to be dropped from the cluster.
In this fix we enable replication of mysql.gtid_slave_pos
table on a cluster. In this way all nodes in a cluster
will know gtid slave position and even after SST joiner
knows correct gtid position to start.
Furthermore, we wait galera to be ready before slave
sql thread executes any events to prevent too early
execution.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
