On Mon, Mar 25, 2013 at 3:51 PM, Bruce Momjian <br...@momjian.us> wrote: > Great analysis. Is there any logic to using a lighter-weight checksum > calculation for cases where the corruption is rare? For example, we > know that network transmission can easily be corrupted, while buffer > corruption is rare, and if corruption happens once, it is likely to > happen again.
It's a matter of use-cases. 16bit (or 32bit, or even 64bit) checksums will never be enough to give good enough guarantees about correctness of data. They are at best the canaries in the coal mine, alerting about underlying issues in the database setup. For our use case one single corruption only has a fraction of a percent of chance of escaping. Multiple errors quickly bring the probability of ignoring corruption into the range of winning two lotteries at once while being struck by lightning. The main thing to look out for is that we don't have any blind spots for conceivable systemic errors. If we decide to go with the SIMD variant then I intend to figure out what the blind spots are and show that they don't matter. Regards, Ants Aasma -- Cybertec Schönig & Schönig GmbH Gröhrmühlgasse 26 A-2700 Wiener Neustadt Web: http://www.postgresql-support.de -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
