Tom Lane wrote: > Curt Sampson <[EMAIL PROTECTED]> writes: > > On Mon, 17 Feb 2003, Tom Lane wrote: > >> Postgres has a bad habit of becoming very confused if the page header of > >> a page on disk has become corrupted. > > > What typically causes this corruption? > > Well, I'd like to know that too. I have seen some cases that were > identified as hardware problems (disk wrote data to wrong sector, RAM > dropped some bits, etc). I'm not convinced that that's the whole story, > but I have nothing to chew on that could lead to identifying a software > bug. > > > If it's any kind of a serious problem, maybe it would be worth keeping > > a CRC of the header at the end of the page somewhere. > > See past discussions about keeping CRCs of page contents. Ultimately > I think it's a significant expenditure of CPU for very marginal returns > --- the layers underneath us are supposed to keep their own CRCs or > other cross-checks, and a very substantial chunk of the problem seems > to be bad RAM, against which occasional software CRC checks aren't > especially useful.
I believe the farthest we got was the idea of adding a CRC page check option in case you suspected bad hardware. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (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 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
