Re: Cost of XLogInsert CRC calculations

"Mark Cave-Ayland" <m.cave-ayland@webbased.co.uk> writes:
> I was just researching some articles on compression (zlib) and I saw mention
> of the Adler-32 algorithm which is supposed to be slightly less accurate
> than an equivalent CRC calculation but significantly faster to compute. I
> haven't located a good paper comparing the error rates of the two different
> checksums,

... probably because there isn't one.  With all due respect to the Zip
guys, I doubt anyone has done anywhere near the analysis on Adler-32
that has been done on CRCs.  I'd much prefer to stick with true CRC
and drop it to 32 bits than go with a less-tested algorithm.  Throwing
more bits at the problem doesn't necessarily create a safer checksum.
        regards, tom lane