Re: Held idle connections vs use of a Pooler

On Tue, 2010-09-14 at 10:10 -0600, mark wrote:
> Hello,
>
> I am relatively new to postgres (just a few months) so apologies if
> any of you are bearing with me.
>
> I am trying to get a rough idea of the amount of bang for the buck I
> might see if I put in a connection pooling service into the enviroment
> vs our current methodology of using persistent open connections.

Well what a pooler does is provide persisten open connections that can
be reused. What tech are you using for these persisten open connections?

> Most of the connections from the various apps hold idle connections
> until they need to execute a query once done go back to holding an
> open idle connection. (there are ~600 open connections at any given
> time, and most of the time most are idle)

Sounds like each app is holding its own pool?

> I think from reading this list for a few weeks the answer is move to
> using connection pooling package elsewhere to better manage incoming
> connections, with a lower number to the db.

Correct, because each connection is overhead. If you have 600
connections, of which really only 20 are currently executing, that is
highly inefficient.

A pooler would have say, 40 connections open, with 20 currently
executing and a max pool of 600.

>
> I am told this will require some re-working of some app code as I
> understand pg-pool was tried a while back in our QA environment and
> server parts of various in-house apps/scripts/..etc started to
> experience show stopping problems.

Use pgbouncer. It is what Skype uses.

Sincerely,

Joshua D. Drake

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