Re: hot_standby_feedback vs. max_standby_archive_delay/max_standby_streaming_delay?

On 8/21/2014 1:44 PM, Steve Kehlet wrote:
> Our queries on our Standby are getting cancelled and so we're
> investigating how to prevent this. The standby is for running periodic
> reporting queries only, we don't care if it falls behind a little bit,
> we just set this guy up to reduce the load on the Primary.
>
> While researching there appear to be several different parameters that
> can help solve this. It sounds like we don't need hot_standby_feedback
> or vacuum_defer_cleanup_age, we really just want to pause things on
> the standby to let it run its queries. So we're going to try
> applying max_standby_archive_delay and max_standby_streaming_delay to
> 1h or so. We're also looking at pg_xlog_replay_pause(), although this
> is less desirable because we don't want to have to ask the people
> running reports to remember to pause and resume things.
>
> Can anyone confirm we're on the right track or provide further
> guidance? Thanks so much.

you will need sufficient wal archiving and/or wal_keep_segments on the
server to cover the worst case period that the slave will get behind due
to pause or whatever.

--
john r pierce 37N 122W
somewhere on the middle of the left coast