| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Laszlo Nagy <gandalf(at)designaproduct(dot)biz> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Poor performance on seq scan |
| Date: | 2006-09-12 20:48:57 |
| Message-ID: | 21446.1158094137@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
Laszlo Nagy <gandalf(at)designaproduct(dot)biz> writes:
> Tom Lane wrote:
>> Why is that showing 85+ percent *system* CPU time??
> I'm sorry, this was really confusing. I don't know what it was -
> probably a background system process, started from cron (?). I retried
> the same query and I got this:
> [ around 80% idle CPU, 10% system, < 10% user ]
OK, so then the thing really is I/O bound, and Luke is barking up the
right tree. The system CPU percentage still seems high though.
I wonder if there is a software aspect to your I/O speed woes ...
could the thing be doing PIO instead of DMA for instance?
regards, tom lane
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