5 Dec
2014
5 Dec
'14
12:01 p.m.
Jonas Oreland <jonaso@google.com> writes:
A slightly off topic question that struck me last night: won't all parallel transactions conflict when updating the slave_gtid_pos table ?
They would, if the GTID was not carefully designed in anticipation of this issue. So the GTID position is updated in slave_gtid_pos with an INSERT, not an UPDATE. This way, multiple updates can be done concurrently. Each row in the gtid_slave_pos table contains an incrementing counter, and the highest value of the counter denotes the "current" row at any one time. I wrote a more detailed explanation of this here: http://kristiannielsen.livejournal.com/17008.html - Kristian.