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

Re: COMMIT NOWAIT Performance Option (patch)

From: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-patches(at)postgresql(dot)org>,<pgsql-hackers(at)postgresql(dot)org>
Subject: Re: COMMIT NOWAIT Performance Option (patch)
Date: 2007-02-26 23:49:33
Message-ID: 1172533773.3760.450.camel@silverbirch.site (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
On Mon, 2007-02-26 at 18:14 -0500, Tom Lane wrote:
> "Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> > A prototype patch is posted to -patches, which is WORK IN PROGRESS.
> > [This patch matches discussion thread on -hackers.]
> 
> What does this accomplish other than adding syntactic sugar over a
> feature that really doesn't work well anyway?  I don't see any point
> in encouraging people to use commit_delay in its present form.  If we
> had a portable solution for millisecond-or-so waits then maybe it would
> work ...

This patch doesn't intend to implement group commit. I've changed the
meaning of commit_delay, sorry if that confuses.

You and I discussed this in Toronto actually, IIRC. The best way to
describe this proposal is deferred fsync, so perhaps a different
parameter commit_fsync_delay would be more appropriate. 

Bruce has requested this feature many times from me, so I thought it
about time to publish.

The key point is that COMMIT NOWAIT doesn't wait for group commit to
return, it just doesn't wait at all - leaving someone else to flush WAL.
It's much better than fsync=off.

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com



In response to

Responses

pgsql-hackers by date

Next:From: Simon RiggsDate: 2007-02-26 23:58:11
Subject: Re: COMMIT NOWAIT Performance Option
Previous:From: Josh BerkusDate: 2007-02-26 23:46:39
Subject: Re: Seeking Google SoC Mentors

pgsql-patches by date

Next:From: ITAGAKI TakahiroDate: 2007-02-27 00:40:48
Subject: Re: Load distributed checkpoint
Previous:From: Tom LaneDate: 2007-02-26 23:14:24
Subject: Re: COMMIT NOWAIT Performance Option (patch)

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