Re: Simplifying wal_sync_method - Mailing list pgsql-hackers

From Magnus Hagander
Subject Re: Simplifying wal_sync_method
Date
Msg-id 6BCB9D8A16AC4241919521715F4D8BCE6C7860@algol.sollentuna.se
Whole thread Raw
In response to Simplifying wal_sync_method  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
> > > Now thinking about it, the guy had corrupt table, not WAL log.
> > > How is WAL->tables synched?  Does the 'wal_sync_method'
> > > affect it or not?
> >
> > I *think* it always fsyncs() there as it is now, but I'm
> not 100% sure.
>
> wal_sync_method is also used to flush pages during a
> checkpoint, so it could lead to table corruption too, not
> just WAL corruption.
>
> However, on Unix, 99% of corruption is caused by bad disk or RAM.

... or iDE disks with write cache enabled. I've certainly seen more than
what I'd call 1% (though I haven't studied it to be sure) that's because
of write-cached disks...

//Magnus


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