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Date: Tue, 3 May 2011 09:08:35 -0500
Message-ID: <BANLkTim_LQ3oMVonYNX5-vbvw6d2A_M7vQ@mail.gmail.com>
Subject: Re: [GENERAL] Can we Flush the Postgres Shared Memory ?
From: Merlin Moncure <mmoncure@gmail.com>
To: =?ISO-8859-1?Q?C=E9dric_Villemain?= <cedric.villemain.debian@gmail.com>
Cc: raghu ram <raghuchennuru@gmail.com>,
	Raghavendra <raghavendra.rao@enterprisedb.com>,
	Simon Riggs <simon@2ndquadrant.com>,
	pgsql-admin <pgsql-admin@postgresql.org>,
	pgsql-general <pgsql-general@postgresql.org>,
	pgsql novice <pgsql-novice@postgresql.org>
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On Tue, May 3, 2011 at 8:55 AM, C=E9dric Villemain
<cedric.villemain.debian@gmail.com> wrote:
> 2011/5/3 Merlin Moncure <mmoncure@gmail.com>:
>>
>> no it will not, or at least there is no guarantee it will be. =A0the
>> only way to reset the buffers in that sense is to restart the database
>> (and even then they might not be read from disk, because they could
>> sit in the o/s cache). =A0to force a read from the drive you'd have to
>> reboot the server, or at least shut it down and use a lot of memory
>> for some other purpose.
>
> with linux, you can : "echo 3 > /proc/sys/vm/drop_caches" for the OS cach=
e
>

yeah -- good point.  aside: does that also drop cache on the drive/raid car=
d?

merlin