[Zope] Trying to trap ConflictError

[David H]

Jonathan wrote:

>
> ----- Original Message ----- From: "David H" <bluepaul at earthlink.net>
> To: "Jonathan" <dev101 at magma.ca>
> Cc: <dieter at handshake.de>; <zope at zope.org>
> Sent: Wednesday, July 05, 2006 3:00 PM
> Subject: Re: [Zope] Trying to trap ConflictError
>
>
>> Jonathan wrote:
>>
>>>
>>> ----- Original Message ----- From: <dieter at handshake.de>
>>> To: "Jonathan" <dev101 at magma.ca>
>>> Cc: "Dennis Allison" <allison at shasta.stanford.edu>; <zope at zope.org>
>>> Sent: Wednesday, July 05, 2006 2:28 PM
>>> Subject: Re: [Zope] Trying to trap ConflictError
>>>
>>>
>>>> Jonathan wrote at 2006-7-4 13:46 -0400:
>>>>
>>>>> ...
>>>>> The image objects stored in
>>>>> TemporaryStorage are never overwritten, edited etc (which is 
>>>>> causing me some
>>>>> confusion as to why the conflict errors are occurring)
>>>>
>>>>
>>>>
>>>> The error message tells your that the conflict is not caused by
>>>> the modification of the image but the container holding your image.
>>>>
>>>> "BTreeFolder" already do conflict resolution -- and reduce the
>>>> conflict probability by about a factor of 30 to 100 (depending on 
>>>> type).
>>>>
>>>> However, if several threads should try to add elements with the same
>>>> id, then the conflict resolution cannot work.
>>>> Maybe, that happens in your case?
>>>
>>>
>>>
>>> The id for the image object is generated by the following code:
>>>
>>> def MakeId():
>>>   time.sleep(.01)
>>>   ts = string.replace(str(time.time()),'.', '')   # remove floating 
>>> point '.' char
>>>   return ts[-10:]
>>>
>>> So there should not be any collision of ids.
>>>
>>> I am still investing, and have found errors like:
>>>
>> Jonathan,
>>
>> I wouldn't feel safe with that.  Why not append a few random digits 
>> just to be safe?
>
>
> I am relatively new to python, so if there is something problematic 
> with my use of the time module to create unique ids, please let me 
> know! (just adding random digits seems a bit kludgy?!)
>
> Thanks,
>
> Jonathan
>
Hi Jonathan,

I figured that if conflicts occur because mutliple processes are 
requesting some service at the same time +- delta then simply generating 
a file name based on the time was suspect. 

David


David