Magnus Hagander wrote:
> > > > 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...
Personally, I can't remember a case that was caused by something other
than bad RAM or bad disk.
Let me write up a section in the manual on this for 8.1, and link it to
the wal_sync_method documentation section, and see how it looks. Even
re-ordering the items in the docs and making bullets has made it clearer
to me what is happening, and what is the default.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
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