Re: max_connections proposal

On 05/26/2011 09:48 PM, Tom Lane wrote:
> Craig Ringer<craig@postnewspapers.com.au>  writes:
>> max_connections = 100                   # (change requires restart)
>> # WARNING: If you're about to increase max_connections above 100, you
>> # should probably be using a connection pool instead. See:
>> #     http://wiki.postgresql.org/max_connections
>
> This gives the impression that performance is great at 100 and falls off
> a cliff at 101, which is both incorrect and likely to lower peoples'
> opinion of the software.

Fair call; the use of a specific value is misleading.

> I'd suggest wording more like "if you're
> considering raising max_connections into the thousands, you should
> probably use a connection pool instead".

Best performance is often obtained with the number of _active_
connections in the 10s to 30s on commonplace hardware. I'd want to use
"hundreds" - because mailing list posts etc suggest that people start
running into problems under load at the 400-500 mark, and more
importantly because it's well worth moving to pooling _way_ before that
point.

> And I agree with Merlin that a
> wiki pointer is inappropriate.

That does make sense.

--
Craig Ringer