On Tue, May 11, 2010 at 7:47 AM, Adam GROSZER <agros...@gmail.com> wrote: > Hello Jim, > > Tuesday, May 11, 2010, 1:37:19 PM, you wrote: > > JF> 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 > > JF> How would a checksum help? All it would do is tell you your hosed. > JF> It wouldn't make you any less hosed. > > Yes, but I would know why it's hosed.
How so? How would you know why it is hosed. Note BTW that the zlib format already includes a checksum. http://www.faqs.org/rfcs/rfc1950.html 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
