Horton

Re: synchronous commit vs. hint bits

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>
Cc: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>, simon@2ndquadrant.com
Date: 2011-12-01T09:09:06Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Allow hint bits to be set sooner for temporary and unlogged tables.

Hi Robert, 
On Wednesday, November 30, 2011 02:10:00 PM Robert Haas wrote:
> On Wed, Nov 30, 2011 at 1:37 AM, YAMAMOTO Takashi
> 
> <yamt@mwd.biglobe.ne.jp> wrote:
> >> Yes, I would expect that.  What kind of increase are you seeing?  Is
> >> it causing a problem for you, or are you just making an observation?
> > 
> > i was curious because my application uses async commits mainly to
> > avoid frequent fsync.  i have no numbers right now.
> Oh, that's interesting.  Why do you want to avoid frequent fsyncs?  I
> thought the point of synchronous_commit=off was to move the fsyncs to
> the background, but not necessarily to decrease the frequency.
Is that so? If it wouldn't avoid fsyncs how could you reach multiple thousand 
TPS in a writing pgbench run on a pretty ordinary system with fsync=on?

Andres