On 1/18/17 8:25 AM, Stephen Frost wrote:
> I was actually thinking about it the other way- start out by changing
> them to both be 5m and then document next to checkpoint_timeout (and
> max_wal_size, perhaps...) that if you go changing those parameters (eg:
> bumping up checkpoint_timeout to 30 minutes and max_wal_size up enough
> that you're still checkpointing based on time and not due to running out
> of WAL space) then you might need to consider raising the timeout for
> pg_ctl to wait around for the server to finish going through crash
> recovery due to all of the outstanding changes since the last
> checkpoint.
It is important for users to be aware of this, but I don't think the
relationship between checkpoint_timeout and recovery time is linear, so
it's unclear what the exact advice should be.
Personally, I think the timeout in pg_ctl is wrong and needs to be
disabled in practical applications, but that is a different discussion.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services