Re: Linux max on shared buffers? - Mailing list pgsql-general

From Curt Sampson
Subject Re: Linux max on shared buffers?
Date
Msg-id Pine.NEB.4.44.0207111251030.436-100000@angelic.cynic.net
Whole thread Raw
In response to Re: Linux max on shared buffers?  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Linux max on shared buffers?
List pgsql-general
On Wed, 10 Jul 2002, Bruce Momjian wrote:

> Woh, 10MB is clearly too low.  Remember, there is copying overhead of
> moving data from the kernel to the PostgreSQL shared buffers.

Yes, but the cost of copying between a postgres buffer and an OS buffer
is much, much less than the cost of copying between an OS buffer and disk.

However, it all depends on your working set, doesn't it? So I can't make
a strong argument either way. What do you think is better? 20 MB? 100
MB? Do you allocate based on the number of connections, or a proportion
of the machine's memory, or something else? I was estimating based on
the number of connections.

cjs
--
Curt Sampson  <cjs@cynic.net>   +81 90 7737 2974   http://www.netbsd.org
    Don't you know, in this new Dark Age, we're all light.  --XTC


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