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el at webmail.exetel.com.au>    <201003202324.o2KNOrlX006114 at apollo.backplane.com> <1427.220.233.36.106.1269131275.squirrel at webmail.exetel.com.au>
From: Chris Turner <c.turner at 199technologies.org>
Subject: Re: Machine unresponsive with cache_lock: blocked on... message
Date: Sun, 21 Mar 2010 18:56:26 +0000
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elekktretterr at exemail.com.au wrote:
> question: why is HAMMER using so much memory, causing applications like
> postgres to use swap (and thus run slow).

this response isn't at all hammer related.. but in any case:

Still a bit fuzzy on some the related issues that might be at play here, 
but as I understand it, the postgres data cache uses as much shared 
memory as it 'wants' (e.g. up to max configured) to hold the database 
data - so if this machine was up for a long time, potentially the entire 
database data set is in memory -

and if the data set isn't used very often, it might get swapped out by 
something else running or just from inactivity ..

If you want to keep this from happening, you can set:

kern.ipc.shm_use_phys=1

in /boot/loader.conf