To: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
Cc: Scott Carey <scott@richrelevance.com>,  Tom Lane <tgl@sss.pgh.pa.us>,
	Kevin Grittner <Kevin.Grittner@wicourts.gov>,
	"pgsql-performance\@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Proposal of tunable fix for scalability of 8.4
In-Reply-To: <49BA6175.4060809@sun.com> (Jignesh K. Shah's message of "Fri\,
	13 Mar 2009 09\:36\:53 -0400")
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References: <C5DEE151.33BA%scott@richrelevance.com> <49BA53CF.4020702@sun.com>
	<871vt1609r.fsf@oxford.xeocode.com> <49BA6175.4060809@sun.com>
From: Gregory Stark <stark@enterprisedb.com>
Organization: EnterpriseDB
Date: Fri, 13 Mar 2009 13:54:09 +0000
Message-ID: <87r6114jge.fsf@oxford.xeocode.com>
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"Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:

> Gregory Stark wrote:
>> Keep in mind when you do this that it's not interesting to test a number of
>> connections much larger than the number of processors you have. Once the
>> system reaches 100% cpu usage it would be a misconfigured connection pooler
>> that kept more than that number of connections open.
>
> Greg, Unfortuately the problem is that.. I am trying to reach 100% CPU which
> I cannot and hence I am increasing the user count :-)

The effect of increasing the number of users with a connection pooler would be
to decrease the 200ms sleep time to 0.

This is all assuming the idle time is *between* transactions. If you have idle
time in the middle of transactions things become a lot more tricky. I think we
are missing something to deal with that use case.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Ask me about EnterpriseDB's 24x7 Postgres support!