Re: wal sync method - Mailing list pgsql-performance

From Tom Lane
Subject Re: wal sync method
Date
Msg-id 3867.1141170306@sss.pgh.pa.us
Whole thread Raw
In response to Re: wal sync method  (PFC <lists@peufeu.com>)
Responses Re: wal sync method
List pgsql-performance
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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