Re: posix_fadvsise in base backups

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>
To: pgsql-hackers@postgresql.org
Cc: Magnus Hagander <magnus@hagander.net>
Date: 2011-09-24T15:14:06Z
Lists: pgsql-hackers
Hi,

On Saturday, September 24, 2011 05:08:17 PM Magnus Hagander wrote:
> Attached patch adds a simple call to posix_fadvise with
> POSIX_FADV_DONTNEED on all the files being read when doing a base
> backup, to help the kernel not to trash the filesystem cache.
> 
> Seems like a simple enough fix - in fact, I don't remember why I took
> it out of the original patch :O
> 
> Any reason not to put this in? Is it even safe enough to put into 9.1
> (probably not, but maybe?)
Won't that possibly throw a formerly fully cached database out of the cache?

Andres