From: Greg Stark <gsstark@mit.edu>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org, Michael Clemmons <glassresistor@gmail.com>
Cc: Hannu Krosing <hannu@2ndquadrant.com>
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Subject: Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)
Date: Wed, 3 Feb 2010 11:53:58 +0000
Message-ID: <407d949e1002030353g522f1afev782a97fd755c5926@mail.gmail.com> (raw)
In-Reply-To: <603c8f071002021145x1939c9e7hb2eedc8ae4dfe23e@mail.gmail.com>
References: <4427a97a0912101235x3ade510blcc00d5ce9883c6b6@mail.gmail.com>
<23321.1265133015@sss.pgh.pa.us>
<603c8f071002021014h4b489f44s9014377e1b38dbc7@mail.gmail.com>
<201002021934.18444.andres@anarazel.de>
<603c8f071002021106o5eef7b40r1ed21c9bd05251ec@mail.gmail.com>
<29129.1265139210@sss.pgh.pa.us>
<603c8f071002021145x1939c9e7hb2eedc8ae4dfe23e@mail.gmail.com>
On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> I think you're probably right, but it's not clear what the new name
> should be until we have a comment explaining what the function is
> responsible for.
So I wrote some comments but wasn't going to repost the patch with the
unchanged name without explanation... But I think you're right though
I was looking at it the other way around. I want to have an API for a
two-stage sync and of course if I do that I'll comment it to explain
that clearly.
The gist of the comments was that the function is preparing to fsync
to initiate the i/o early and allow the later fsync to fast -- but
also at the same time have the beneficial side-effect of avoiding
cache poisoning. It's not clear that the two are necessarily linked
though. Perhaps we need two separate apis, though it'll be hard to
keep them separate on all platforms.
--
greg
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Cc: gsstark@mit.edu, robertmhaas@gmail.com, tgl@sss.pgh.pa.us, andres@anarazel.de, glassresistor@gmail.com, hannu@2ndquadrant.com, scott.marlowe@gmail.com
Subject: Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)
In-Reply-To: <407d949e1002030353g522f1afev782a97fd755c5926@mail.gmail.com>
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