percona-discussion team mailing list archive

[MARK CALLAGHAN <mdcallag@xxxxxxxxx>]

On Thu, Apr 30, 2009 at 8:59 PM, Baron Schwartz <baron@xxxxxxxxx> wrote:

>
> Yeah, but... changing checksum would instantly result in all pages
> being "corrupt", no?

Yes, so it warrants a new Innodb file format: antelope, barracuda, .... checksum
As soon as I get a nehalem I will find out how much faster HW support
for crc helps.

Eventually, xtra-backup may get far enough along that you need to
introduce a new InnoDB file format and at that point you can change
the file format.

>
>> But there's an additional issue with the whole checksum foo. The checksum is
>> right next to the data, and while CRCs are decent at detecting corruption,
>> the proximity can also hide some occurrances. ZFS has the nifty trick of
>> storing checksums separately, and I think that's quite brilliant. Not saying
>> it's easy to do for InnoDB or even if it's desirable - just want to put it
>> out there so we can discuss.
>
> I think it's a really good design.  It seems "hard" at this stage in
> InnoDB's life, though.
>
> What about PBXT or Maria?  I don't even know if they checksum data.
>



-- 
Mark Callaghan
mdcallag@xxxxxxxxx