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Re: Performance problems testing with Spamassassin 3.1.0

From: Andrew McMillan <andrew(at)catalyst(dot)net(dot)nz>
To: Matthew Schumacher <matt(dot)s(at)aptalaska(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Performance problems testing with Spamassassin 3.1.0
Date: 2005-07-29 20:19:31
Message-ID: 1122668371.5691.352.camel@lamb.mcmillan.net.nz (view raw or flat)
Thread:
Lists: pgsql-performance
On Fri, 2005-07-29 at 09:37 -0800, Matthew Schumacher wrote:
> > 
> > On my laptop this takes:
> > 
> > real    1m33.758s
> > user    0m4.285s
> > sys     0m1.181s
> > 
> > One interesting effect is the data in bayes_vars has a huge number of
> > updates and needs vacuum _frequently_.  After the run a vacuum full
> > compacts it down from 461 pages to 1 page.
> > 
> 
> I wonder why your laptop is so much faster.  My 2 min 30 sec test was
> done on a dual xeon with a LSI megaraid with 128MB cache and writeback
> caching turned on.

I only do development stuff on my laptop, and all of my databases are
reconstructable from copies, etc...  so I turn off fsync in this case.


> How often should this table be vacuumed, every 5 minutes?

I would be tempted to vacuum after each e-mail, in this case.


> Also, this test goes a bit faster with sync turned off, if mysql isn't
> using sync that would be why it's so much faster.  Anyone know what the
> default for mysql is?

It depends on your table type for MySQL.

For the data in question (i.e. bayes scoring) it would seem that not
much would be lost if you did have to restore your data from a day old
backup, so perhaps fsync=false is OK for this particular application.

Regards,
					Andrew McMillan.

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Subject: Re: Performance problems testing with Spamassassin 3.1.0
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