Re: JDBC and processing large numbers of rows

From: Oliver Jowett <oliver(at)opencloud(dot)com>
To: Guido Fiala <guido(dot)fiala(at)dka-gmbh(dot)de>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: JDBC and processing large numbers of rows
Date: 2004-05-12 13:23:16
Message-ID: 40A22544.8000206@opencloud.com
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Guido Fiala wrote:
> Am Mittwoch, 12. Mai 2004 12:00 schrieb Kris Jurka:
>
>>The backend spools to a file when a materialized cursor uses more than
>>sort_mem amount of memory. This is not quite the same as swapping as it
>>will consume disk bandwidth, but it won't hog memory from other
>>applications.
>
>
> Well thats good on one side, but from the side of the user its worse:
>
> He will see a large drop in performance (factor 1000) ASAP the database starts
> using disk for such things. Ok - once the database is to large to be hold in
> memory it is disk-bandwith-limited anyway...

What about the kernel cache? I doubt you'll see a *sudden* drop in
performance .. it'll just degrade gradually towards disk speeds as your
resultset gets larger.

-O

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