Обсуждение: AW: Uh, this is *not* a 64-bit CRC ...

> I just took a close look at the COMP_CRC64 macro in xlog.c.
> 
> This isn't a 64-bit CRC.  It's two independent 32-bit CRCs, one done
> on just the odd-numbered bytes and one on just the even-numbered bytes
> of the datastream.  That's hardly any stronger than a single 
> 32-bit CRC;
> it's certainly not what I thought we had agreed to implement.

Hmm, strange. I thought that we had agreed upon a 32 bit CRC
on the grounds, that it would be strong enough to guard a single
log record.

Andreas

Zeugswetter Andreas SB  <ZeugswetterA@wien.spardat.at> writes:
>> it's certainly not what I thought we had agreed to implement.

> Hmm, strange. I thought that we had agreed upon a 32 bit CRC
> on the grounds, that it would be strong enough to guard a single
> log record.

I thought that, and still think it, but I was outvoted.  However I
see no value in the present actual implementation ...
        regards, tom lane