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Date: Wed, 2 Oct 2013 07:58:45 -0700 (PDT)
From: Kevin Grittner <kgrittn@ymail.com>
Reply-To: Kevin Grittner <kgrittn@ymail.com>
Subject: Re: Random server overload
To: Igor Neyman <ineyman@perceptron.com>, Viktor <viktor@okservers.eu>,
 "pgsql-admin@postgresql.org" <pgsql-admin@postgresql.org>
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Igor Neyman <ineyman@perceptron.com> wrote:

>> Our Java application uses c3p0 connection pooler and we don't
>> think that it's the issue.
>
> "Client-side" connection pooling is different from server-side
> (such as PgBouncer), and I believe is not as effective as
> PgBouncer.

In my experience a good client-side pooler can be more effective --
if all significant traffic is going through a single pooler and the
pool size is set appropriately.=A0 For example, we improved
performance on a 16 code 256 GB server by reducing the pool size of
the web application (handling hundreds of requests per second from
3000 concurrent users) from a maximum of 60 database connections to
35.

http://wiki.postgresql.org/wiki/Number_Of_Database_Connections

> As you stated in original message you have multiple idle
> connections, that's waste of resources.

... and a risk that if they all become active at one time, you can
have a seemingly-random server overload.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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