Horton

Re: Wierd context-switching issue on Xeon

Josh Berkus <josh@agliodbs.com>

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From: Josh Berkus <josh@agliodbs.com>
To: Joe Conway <mail@joeconway.com>, "scott.marlowe" <scott.marlowe@ihs.com>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Tom Lane <tgl@sss.pgh.pa.us>, lutzeb@aeccom.com, pgsql-performance@postgresql.org, Neil Conway <neilc@samurai.com>
Date: 2004-04-19T21:55:04Z
Lists: pgsql-performance 
Joe,

> I've got a quad 2.8Ghz MP Xeon (IBM x445) that I could test on. Does 
> anyone have a test set that can reliably reproduce the problem?

Unfortunately we can't seem to come up with one.    So far we have 2 machines 
that exhibit the issue, and their databases are highly confidential (State of 
WA education data).  

It does seem to require a database which is in the many GB (> 10GB), and a 
situation where a small subset of the data is getting hit repeatedly by 
multiple processes.   So you could try your own data warehouse, making sure 
that you have at least 4 connections hitting one query after another.

-- 
-Josh Berkus
 Aglio Database Solutions
 San Francisco