Re: Poor performance on seq scan

Laszlo Nagy <gandalf@designaproduct.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