Wow! That is a huge difference. I wish we could make
fdatasync/datasync use automatic. We can't now because sometimes
fdatasync is just a stub for fsync, and in those cases open_fsync may be
a better option. I would really like some ideas on automatic
configuration.
> > Date: Wed, 12 Sep 2001 14:19:09 +0200 (CEST)
> > From: Peter Eisentraut <peter_e@gmx.net>
> > To: Kenji Sugita <sugita@sra.co.jp>
> > Subject: Re: [PATCHES] Configuring fdatasync for Solaris2
> >
> > > I also cannot find out the rt library on Solaris2. The library posix4 hits
> > > fdatasync.
> >
> > I rechecked the manuals, apparently -lrt was added in a later version
> > (after the POSIX.4 group was renamed?). I've changed the test to check
> > both libraries.
>
> Thanks a lot.
>
> > Do you have any performance data of the fdatasync method versus the
> > default open_datasync method?
>
> I have the data for SPARC 500MHz Solaris2.6 running PostgreSQL 7.1.3.
>
> #clients open_datasync fdatasync (TPC-B, TPS)
> ======== ============= =========
> 1 34.867522 47.188265
> 2 41.457329 57.119142
> 4 41.854741 62.250403
> 8 43.103382 63.909396
> 16 35.890254 62.757908
> 32 41.421592 52.132258
> 64 37.325511 51.805046
> 128 28.906521 37.942672
>
> This table is made by following commands:
>
> pgbench -i -s 10
> pgbench -c #clients -t 100
>
> > Peter Eisentraut peter_e@gmx.net http://funkturm.homeip.net/~peter
>
>
> Kenji Sugita
> sugita@sra.co.jp
>
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--
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