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) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
