To: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
Cc: Greg Smith <gsmith@gregsmith.com>,
	"pgsql-performance\@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: 8.4 Performance improvements: was Re: Proposal of tunable fix for
	scalability of 8.4
In-Reply-To: <49BA5537.8060002@sun.com> (Jignesh K. Shah's message of "Fri\,
	13 Mar 2009 08\:44\:39 -0400")
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References: <C5DDBB25.3333%scott@richrelevance.com> <49B922C0.6050700@sun.com>
	<alpine.GSO.2.01.0903121613270.1925@westnet.com>
	<49BA5537.8060002@sun.com>
From: Gregory Stark <stark@enterprisedb.com>
Organization: EnterpriseDB
Date: Fri, 13 Mar 2009 13:57:06 +0000
Message-ID: <87prgl4jbh.fsf@oxford.xeocode.com>
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A minute ago I said:

 AFAIK Opensolaris doesn't implement posix_fadvise() so there's no benefit. It
 would be great to hear if you could catch the ear of the right people to get
 an implementation committed. Depending on how the i/o scheduler system is
 written it might not even be hard -- the Linux implementation of WILLNEED is
 all of 20 lines.

I noticed after sending it that that's slightly unfair. The 20-line function
calls another function (which calls another function) to do the real readahead
work. That function (mm/readahead.c:__do_page_cache_readahead()) is 48 lines.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Ask me about EnterpriseDB's Slony Replication support!