The event *arrives* pretty soon after - unless you have a flaky network,
that's not really you should worry about.
The major timing issue will be when an event will get *executed* on the
slave, and the answer is: it varies. Events get executed sequentially on the
slave, so although it will generally be fast (order of milliseconds), a huge
update or other long-running query will block the queue until it finishes,
and thus you could see the occasional multisecond delay.
It all depends on your workload, though.
2010/1/27 Miguel Araújo <noradone@stripped>
> Hello.
>
> I want to measure replication speed for a great number of replicas. By that
> I mean how soon an event arrives at the slave after being logger to the
> master's binary log.
>
> So, I've started developing an application to read the replication logs in
> order to compare them (compare by time, the log position on the master node
> with the log position on the slave's). My first approach was to use the
> mysqlbinlog to get the log position, in the 'Master_Log_File'. But in the
> slave's the last position that the SQL thread has read and executed is the
> 'Relay_Log_Pos', right?
> I have to read the slave's relay log, in order to get the last position on
> the Master's log executed? And compare with the master's log?
>
> Thank you.
>
> Regards,
> Miguel Araújo
>
>
>
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