Re: O_DSYNC broken on MacOS X? - Mailing list pgsql-hackers

From Dave Page
Subject Re: O_DSYNC broken on MacOS X?
Date
Msg-id AANLkTinRhC31dGc-04H=H9z+NRHBfLpS20hkq9mUe91s@mail.gmail.com
Whole thread Raw
In response to O_DSYNC broken on MacOS X?  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Thu, Sep 30, 2010 at 8:26 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> Jayant Kumar did some benchmarking of InnoDB vs. PostgreSQL and PG
> came out 5 times faster.  The benchmark isn't very thoroughly
> described, but it turns out not to matter.
>
> http://jayant7k.blogspot.com/2010/09/database-speed-tests-mysql-and.html
>
> Apparently, the reason we're faster is that wal_sync_method =
> open_datasync, which is the default on MacOS X, doesn't actually work.

That might be true, but if you check the comments, Jayant replied to say:

@Andrew : I am running linux - ubuntu 10.04 - kernel 2.6.32-24. Linux
does not support fsync_writethrough
http://www.westnet.com/~gsmith/content/postgresql/TuningPGWAL.htm

So I don't think that invalidates his benchmark. Something else might
of course...

--
Dave Page
Blog: http://pgsnake.blogspot.com
Twitter: @pgsnake

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