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Message-ID: <4DDCC32D.2000901@gmail.com>
Date: Wed, 25 May 2011 11:51:57 +0300
From: Vitalii Tymchyshyn <tivv00@gmail.com>
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To: Greg Smith <greg@2ndQuadrant.com>
CC: pgsql-performance@postgresql.org
Subject: Re: [PERFORMANCE] expanding to SAN: which portion best
 to move
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24.05.11 21:48, Greg Smith написав(ла):
>
> Bitmap heap scan: Here, the exact list of blocks to fetch is known in 
> advance, they're random, and it's quite possible for the kernel to 
> schedule them more efficiently than serial access of them can do. This 
> was added as the effective_io_concurrency feature (it's the only thing 
> that feature impacts), which so far is only proven to work on Linux. 
> Any OS implementing the POSIX API used will also get this however; 
> FreeBSD was the next likely candidate that might benefit when I last 
> looked around.
FreeBSD unfortunately do not have the support :(
It has AIO, but does not have the call needed to enable this settings.

Best regards, Vitalii Tymchyshyn