The assertion occurred in the SQL thread if an event group was incompletely
written, missing the end XID or COMMIT event, and immediately followed by a
new event group. This could also lead to the incomplete event group being
committed, and with the wrong GTID.
Fix by rolling back any active transaction from a prior event group when
applying the following GTID event.
Getting an incomplete event like this is somewhat rare to happen. If the
server crashes in the middle of writing an event group, the server restart
will write a new format description event, which makes the slave roll back
the partial event group. But presumably it could happen if the master
experiences temporary write errors in the binlog, like intermittent disk
full for example.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
