Re: Interesting incosistent query timing - Mailing list pgsql-performance

From Ernest E Vogelsinger
Subject Re: Interesting incosistent query timing
Date
Msg-id 5.1.1.6.2.20030617044100.02dd1c70@mail.vogelsinger.at
Whole thread Raw
In response to Interesting incosistent query timing  (Ernest E Vogelsinger <ernest@vogelsinger.at>)
List pgsql-performance
At 04:20 17.06.2003, Nikolaus Dilger said:
--------------------[snip]--------------------
>My guess is that the second execution of the query is
>shorter since the data blocks are cached in memory.
>When you modify the data then it needs to be read again
>from disk which is much slower than from memory.  The
>short execution after restarting PostgreSQL seems to
>indicate that your data is cached in the Linux buffer
>cache.
>
>The only strange thing seems to be that you have so few
>rows.  Are you getting the data from a remote machine?
>How many bytes does a single row have?  Are they really
>large???
--------------------[snip]--------------------

What exactly do you mean? This table is quite filled (2.3 million rows),
but the query results are correct.


--
   >O     Ernest E. Vogelsinger
   (\)    ICQ #13394035
    ^     http://www.vogelsinger.at/



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