From: Tom Lane <tgl@sss.pgh.pa.us>
To: PFC <lists@peufeu.com>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Javier Somoza <jsomoza@pandasoftware.es>
Cc: Evgeny Gridasov <eugrid@fpm.kubsu.ru>
Cc: pgsql-performance@postgresql.org
Subject: Re: wal sync method
Date: Tue, 28 Feb 2006 18:45:06 -0500
Message-ID: <3867.1141170306@sss.pgh.pa.us> (raw)
In-Reply-To: <op.s5piavelcigqcu@apollo13>
References: <200602280114.k1S1EAQ17159@candle.pha.pa.us>
<op.s5piavelcigqcu@apollo13>
PFC <lists@peufeu.com> writes:
> Just a stupid question about the various fsync settings.
> There is fsync=off, but is there fsync=fflush ?
> fflush would mean only an OS crash could cause data loss,
> I think.it could be useful for some applications where you need a speed
> boost (like testing database import scripts...) without being as scary as
> fsync=off...
I think you misunderstand. There aren't any scenarios where a PG crash
(without hardware/OS crash) risks data, because we always at least
write() data before commit. The only issue is how hard do we try to get
the OS+hardware to push that data down to disk.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, lists@peufeu.com, pgman@candle.pha.pa.us, jsomoza@pandasoftware.es, eugrid@fpm.kubsu.ru
Subject: Re: wal sync method
In-Reply-To: <3867.1141170306@sss.pgh.pa.us>
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