Re: Page Checksums

* Aidan Van Dyk (aidan(at)highrise(dot)ca) wrote:
> But the scary part is you don't know how long *ago* the crash was.
> Because a hint-bit-only change w/ a torn-page is a "non event" in
> PostgreSQL *DESIGN*, on crash recovery, it doesn't do anything to try
> and "scrub" every page in the database.

Fair enough, but, could we distinguish these two cases? In other words,
would it be possible to detect if a page was torn due to a 'traditional'
crash and not complain in that case, but complain if there's a CRC
failure and it *doesn't* look like a torn page?

Perhaps that's a stretch, but if we can figure out that a page is torn
already, then perhaps it's not so far fetched..

Thanks,

Stephen
(who is no expert on WAL/torn pages/etc)