Re: How to keep queries low latency as concurrency increases - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: How to keep queries low latency as concurrency increases
Date
Msg-id CAOR=d=19_2nFHFSQmFkbzEk+nq9jT=utWGsMQ64_nqiOLn31Hw@mail.gmail.com
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In response to Re: How to keep queries low latency as concurrency increases  (Greg Williamson <gwilliamson39@yahoo.com>)
Responses Re: How to keep queries low latency as concurrency increases
List pgsql-performance
On Tue, Oct 30, 2012 at 4:11 PM, Greg Williamson
<gwilliamson39@yahoo.com> wrote:
> Jeff / Catalin --
>
> Jeff Janes wrote:
>
>>On Mon, Oct 29, 2012 at 5:11 PM, Catalin Iacob <iacobcatalin@gmail.com> wrote:
>>
>>> pgbouncer 1.4.2 installed from Ubuntu's packages on the same machine
>>> as Postgres. Django connects via TCP/IP to pgbouncer (it does one
>>> connection and one transaction per request) and pgbouncer keeps
>>> connections open to Postgres via Unix socket.
>>
>>Isn't pgbouncer single-threaded?
>>
>>If you hitting it with tiny queries as fast as possible from 20
>>connections, I would think that it would become the bottleneck.
>>
>>Cheers,
>>
>
>
> I'm sure pgbouncer has some threshold where it breaks down, but we have servers (postgres 8.4 and 9.1) with
connectionsfrom runtime (fed via haproxy) to pgbouncer that routinely have tens of thousands of connections in but only
40-70postgres connections to the postgres cluster itself. Mix of queries but most are simple. Typically a few thousand
queriesa second to the readonly boxes, about the same to a beefier read / write master. 
>
> This is a slightly old pgbouncer at that ... used is a fairly basic mode.

I've used pgbouncer in two different environments now with thousands
of connections and hundreds upon hundreds of queries per second and it
has yet to be a bottleneck in either place as well.


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