Kristian Nielsen <knielsen@knielsen-hq.org> writes:
- Should Seconds_Behind_Master be changed as per above in parallel replication (from 10.0 on)?
- If so, should the change to Seconds_Behind_Master also be done in the non-parallel case in 10.1? What about 10.0?
So there seems to be agreement that Seconds_Behind_Master should be changed in 10.1 to only update on commit (also in non-parallel case). This does seem a better behaviour. One consequence of this is the following: Suppose the master is idle for 1 hour. The Seconds_Behind_Master is reported as 0 on a slave that is up to date. Suppose now the master executes a transaction. While that new transaction is being applied, the Seconds_Behind_Master will be reported as 3600 (one hour), then go back to zero. This is arguably the correct value - the slave is indeed in the state of the master one hour ago while executing that transaction. But I still wonder if this will not just cause another kind of confusion with users (or existing monitoring tools), as they will interpret it as the slave being far behind the master. While in reality it is only one transaction behind. - Kristian.