Re: Linux mis-reporting memory - Mailing list pgsql-performance

From Csaba Nagy
Subject Re: Linux mis-reporting memory
Date
Msg-id 1190374462.4661.199.camel@PCD12478
Whole thread Raw
In response to Re: Linux mis-reporting memory  ("Heikki Linnakangas" <heikki@enterprisedb.com>)
List pgsql-performance
On Fri, 2007-09-21 at 11:34 +0100, Heikki Linnakangas wrote:
> Which version of Postgres is this? In 8.3, a scan like that really won't
> suck it all into the shared buffer cache. For seq scans on tables larger
> than shared_buffers/4, it switches to the bulk read strategy, using only
>  a few buffers, and choosing the starting point with the scan
> synchronization facility.
>
This was on 8.1.9 installed via apt-get on Debian 4.1.1-21. In any case
I'm pretty sure linux swaps shared buffers, as I always got worse
performance for shared buffers more than about 1/3 of the memory. But in
that case the output of top is misleading.

Cheers,
Csaba.



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