Re: Page Checksums

On Wed, Dec 21, 2011 at 09:32:28AM +0100, Leonardo Francalanci wrote:
> I can't help in this discussion, but I have a question:
> how different would this feature be from filesystem-level CRC, such
> as the one available in ZFS and btrfs?

Hmm, filesystems are not magical. If they implement this then they will
have the same issues with torn pages as Postgres would.  Which I
imagine they solve by doing a transactional update by writing the new
page to a new location, with checksum and updating a pointer.  They
can't even put the checksum on the same page, like we could.  How that
interacts with seqscans I have no idea.

Certainly I think we could look to them for implementation ideas, but I
don't imagine they've got something that can't be specialised for
better performence.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> He who writes carelessly confesses thereby at the very outset that he does
> not attach much importance to his own thoughts.  -- Arthur Schopenhauer