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

From: Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "'pgsql-hackers(at)postgresql(dot)org'" <pgsql-hackers(at)postgresql(dot)org>
Subject: AW: Uh, this is *not* a 64-bit CRC ...
Date: 2001-03-01 08:06:46
Message-ID: 11C1E6749A55D411A9670001FA68796336821D@sdexcsrv1.f000.d0188.sd.spardat.at
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> 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

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