Re: 9.4 regression

From: Thom Brown <thom(at)linux(dot)com>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Stephen Frost <sfrost(at)snowman(dot)net>, Andres Freund <andres(at)2ndquadrant(dot)com>, Jon Nelson <jnelson+pgsql(at)jamponi(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: 9.4 regression
Date: 2013-10-24 10:41:11
Message-ID: CAA-aLv7ywgGub=S-T4enPDya8azEKC9XhNx8bTF8jJEHgqOFiA@mail.gmail.com
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On 5 September 2013 22:24, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> On Mon, Aug 19, 2013 at 09:27:57PM -0400, Stephen Frost wrote:
>> * Andres Freund (andres(at)2ndquadrant(dot)com) wrote:
>> > I vote for adapting the patch to additionally zero out the file via
>> > write(). In your tests that seemed to perform at least as good as the
>> > old method... It also has the advantage that we can use it a littlebit
>> > more as a testbed for possibly using it for heap extensions one day.
>> > We're pretty early in the cycle, so I am not worried about this too much...
>>
>> I dunno, I'm pretty disappointed that this doesn't actually improve
>> things. Just following this casually, it looks like it might be some
>> kind of locking issue in the kernel that's causing it to be slower; or
>> at least some code path that isn't exercise terribly much and therefore
>> hasn't been given the love that it should.
>>
>> Definitely interested in what Ts'o says, but if we can't figure out why
>> it's slower *without* writing out the zeros, I'd say we punt on this
>> until Linux and the other OS folks improve the situation.
>
> FYI, the patch has been reverted.

Is there an updated patch available for this? And did anyone hear from Ts'o?

--
Thom

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