Re: Proposal of tunable fix for scalability of 8.4 - Mailing list pgsql-performance

From Gregory Stark
Subject Re: Proposal of tunable fix for scalability of 8.4
Date
Msg-id 87r6114jge.fsf@oxford.xeocode.com
Whole thread Raw
In response to Re: Proposal of tunable fix for scalability of 8.4  ("Jignesh K. Shah" <J.K.Shah@Sun.COM>)
List pgsql-performance
"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!

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