Re: PostgreSQL Cache

From: Sam Mason <sam(at)samason(dot)me(dot)uk>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: PostgreSQL Cache
Date: 2008-09-29 11:26:34
Message-ID: 20080929112634.GM7271@frubble.xen.chris-lamb.co.uk
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On Mon, Sep 29, 2008 at 02:55:52AM -0400, Greg Smith wrote:
> On Mon, 29 Sep 2008, Matthew Pulis wrote:
> >I need to perform some timed testing, thus need to make sure that
> >disk cache does not affect me. Is clearing the OS (Ubuntu) disk
> >cache, (by running: sudo echo 3 | sudo tee /proc/sys/vm/drop_caches)
> >enough to do this?
>
> 3) sudo echo 3 > /proc/sys/vm/drop_caches

I'm not sure about the rest, but shouldn't this be:

echo 3 | sudo tee /proc/sys/vm/drop_caches

the OP's "sudo echo 3" seems redundant; "echo" doesn't need to be run
with higher privileges, only the writing process needs that. As an
aside, it would be nicer if there was a more appropriately program than
tee but I've yet to find one.

Sam

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