Strange duplication of dives

Dirk Hohndel dirk at hohndel.org
Sun Dec 16 09:40:00 PST 2012


Jef Driesen <jefdriesen at telenet.be> writes:

>>> @subsurface dev's: Shouldn't the diveid hash that was introduced some time ago
>>> catch this? The raw timestamp in the dive doesn't change, only the parsed
>>> date/time value.
>>
>> The diveid is simply part of the SHA1 hash of the fingerprint of the
>> dive. I assume that contains the raw timestamp, correct?
>
> For the sensuspro, the libdivecomputer fingerprint is indeed the 4 byte raw 
> timestamp. So the fingerprint (or its hash) is invariant and thus should have 
> triggered the cut off, regardless of whether the final date/time value is 
> different or not.

Hmm, so something is broken there...

>> We used to cut off downloads by saying "this dive was prior to the last
>> dive that we already have" - much simpler and certainly prevented what
>> happened to you...
>
> That's not entirely correct. If the duplicate gets a time that is greater than 
> the time of the dive you already have, you would still get a duplicate.

True. But you wouldn't get lots of duplicates, all off by a minute or
two...

/D


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