On Tue, May 11, 2010 at 7:13 AM, Adam GROSZER <agros...@gmail.com> wrote: > Hello Jim, > > Tuesday, May 11, 2010, 12:33:04 PM, you wrote: > > JF> On Tue, May 11, 2010 at 3:16 AM, Adam GROSZER <agros...@gmail.com> wrote: >>> Hello Jim, >>> >>> Monday, May 10, 2010, 1:27:00 PM, you wrote: >>> >>> JF> On Sun, May 9, 2010 at 4:59 PM, Roel Bruggink <r...@fourdigits.nl> >>> wrote: >>>>> That's really interesting! Did you notice any issues performance wise, or >>>>> didn't you check that yet? >>> >>> JF> I didn't check performance. I just iterated over a file storage file, >>> JF> checking compressed and uncompressed pickle sizes. >>> >>> I'd say some checksum is then also needed to detect bit failures that >>> mess up the compressed data. > > JF> Why? > > I think the gzip algo compresses to a bit-stream, where even one bit > has an error the rest of the uncompressed data might be a total mess. > If that one bit is relatively early in the stream it's fatal. > Salvaging the data is not a joy either. > I know at this level we should expect that the OS and any underlying > infrastructure should provide error-free data or fail. > Tho I've seen some magic situations where the file copied without > error through a network, but at the end CRC check failed on it :-O
How would a checksum help? All it would do is tell you your hosed. It wouldn't make you any less hosed. Jim -- Jim Fulton _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
