Message-ID: <53E27B13.50506@vmware.com>
Date: Wed, 6 Aug 2014 21:59:31 +0300
From: Heikki Linnakangas <hlinnakangas@vmware.com>
Organization: VMware
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To: Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development
 <pgsql-hackers@postgresql.org>
Subject: Re: posix_fadvise() and pg_receivexlog
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On 08/06/2014 08:39 PM, Fujii Masao wrote:
> Hi,
>
> The WAL files that pg_receivexlog writes will not be re-read soon basically,
> so we can advise the OS to release any cached pages when WAL file is
> closed. I feel inclined to change pg_receivexlog that way. Thought?

-1. The OS should be smart enough to not thrash the cache by files that 
are written sequentially and never read. If we go down this path, we'd 
need to sprinkle posix_fadvises into many, many places.

Anyway, who are we to say that they won't be re-read soon? You might e.g 
have a secondary backup site where you copy the files received by 
pg_receivexlog, as soon as they're completed.

- Heikki


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