[ZODB-Dev] Some interesting (to some:) numbers

[Adam GROSZER]

Hello Jim,

Tuesday, May 11, 2010, 12:33:04 PM, you wrote:

JF> On Tue, May 11, 2010 at 3:16 AM, Adam GROSZER <agroszer at 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 <roel at 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

-- 
Best regards,
 Adam GROSZER                            mailto:agroszer at gmail.com
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