| From: | Steve Atkins <steve(at)blighty(dot)com> |
|---|---|
| To: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Planner constants for RAM resident databases |
| Date: | 2005-07-02 02:08:23 |
| Message-ID: | 20050702020823.GA32264@gp.word-to-the-wise.com |
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| Lists: | pgsql-performance |
On Fri, Jul 01, 2005 at 09:59:38PM -0400, Emil Briggs wrote:
> I'm working with an application where the database is entirely resident in RAM
> (the server is a quad opteron with 16GBytes of memory). It's a web
> application and handles a high volume of queries. The planner seems to be
> generating poor plans for some of our queries which I can fix by raising
> cpu_tuple_cost. I have seen some other comments in the archives saying that
> this is a bad idea but is that necessarily the case when the database is
> entirely resident in RAM?
If I'm understanding correctly that'll mostly increase the estimated
cost of handling a row relative to a sequential page fetch, which
sure sounds like it'll push plans in the right direction, but it
doesn't sound like the right knob to twiddle.
What do you have random_page_cost set to?
Cheers,
Steve
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