Re: large tables and simple "= constant" queries using indexes

From: John Beaver <john(dot)e(dot)beaver(at)gmail(dot)com>
To: Gaetano Mendola <mendola(at)gmail(dot)com>, Pgsql-Performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: large tables and simple "= constant" queries using indexes
Date: 2008-04-10 16:37:45
Message-ID: 47FE4259.7030704@gmail.com
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Thanks Eric and Gaestano - interesting, and both examples of my
naivite. :)<br>
<br>
I tried running large select(*) queries on other tables followed by
another try at the offending query, and it was still fast. Just to be
absolutely sure this is a scalable solution, I'll try restarting my
computer in a few hours to see if it affects anything cache-wise.<br>
<br>
<br>
Gaetano Mendola wrote:
<blockquote cite="mid:47FE3DC7(dot)4010700(at)gmail(dot)com" type="cite">
<pre wrap="">John Beaver wrote:

</pre>
<blockquote type="cite">
<pre wrap="">- Trying the same constant a second time gave an instantaneous result,
I'm guessing because of query/result caching.
</pre>
</blockquote>
<pre wrap=""><!---->
AFAIK no query/result caching is in place in postgres, what you are experiencing
is OS disk/memory caching.

Regards
Gaetano Mendola

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