From: | Mike Rylander <mrylander(at)gmail(dot)com> |
---|---|
To: | Yudie Pg <yudiepg(at)gmail(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: How to speed up word count in tsearch2? |
Date: | 2005-04-01 12:17:56 |
Message-ID: | b918cf3d0504010417476720ad@mail.gmail.com |
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Lists: | pgsql-performance |
On Apr 1, 2005 4:03 AM, Yudie Pg <yudiepg(at)gmail(dot)com> wrote:
> > You need to look at what else is using RAM on that machine. And maybe buy
> > more.
>
> Ouch.. I had that feeling also. then how can I know how much memory
> needed for certain amount words? and why counting uncommon words are
> faster than common one?
Because the index is a tree. You fall of the end of a branch faster
with uncommon words. Plus the executor goes back to the table for
fewer real rows with uncommon words.
It sounds like you may just need a faster disk subsystem. That would
shrink the time for the first query on any particular set of words,
and it would make everything else faster as a nice side effect. What
does your disk layout look like now?
--
Mike Rylander
mrylander(at)gmail(dot)com
GPLS -- PINES Development
Database Developer
http://open-ils.org
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