Skip site navigation (1) Skip section navigation (2)

Re: [HACKERS] data on devel code perf dip

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Mark Wong <markw(at)osdl(dot)org>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, maryedie(at)osdl(dot)org,PostgreSQL-patches <pgsql-patches(at)postgresql(dot)org>,Josh Berkus <josh(at)agliodbs(dot)com>
Subject: Re: [HACKERS] data on devel code perf dip
Date: 2005-08-12 16:12:17
Message-ID: 200508121612.j7CGCHT03271@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
Mark Wong wrote:
> On Thu, 11 Aug 2005 22:11:42 -0400 (EDT)
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> wrote:
> 
> > Tom Lane wrote:
> > > Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > > >> O_DIRECT is only being used for WAL page writes (or I sure hope so
> > > >> anyway), so shared_buffers should be irrelevant.
> > > 
> > > > Uh, O_DIRECT really just enables when open_sync is used, and I assume
> > > > that is not used for writing dirty buffers during a checkpoint.
> > > 
> > > I double-checked that O_DIRECT is really just used for WAL, and only
> > > when the sync mode is open_sync or open_datasync.  So it seems
> > > impossible that it affected a run with mode fdatasync.  What seems the
> > > best theory at the moment is that the grouped-WAL-write part of the
> > > patch doesn't work so well as we thought.
> > 
> > Yes, that's my only guess.  Let us know if you want the patch to test,
> > rather than pulling CVS before and after the patch was applied.
> 
> Yeah, a patch would be a little easier. :)

OK, patch attached. The code has been cleaned up a little since then but
this is the basic change that should be tested.  It is based on CVS of
2005/07/29 03:22:33 GMT.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

In response to

Responses

pgsql-hackers by date

Next:From: Alvaro HerreraDate: 2005-08-12 16:12:20
Subject: CREATE TABLE synopsis
Previous:From: Mark WongDate: 2005-08-12 15:43:10
Subject: Re: data on devel code perf dip

pgsql-patches by date

Next:From: Alvaro HerreraDate: 2005-08-12 16:37:22
Subject: createuser patch
Previous:From: Bruce MomjianDate: 2005-08-12 15:59:06
Subject: Re: [HACKERS] For review: Server instrumentation patch

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group