Serge

Yup, I was blind and used "finally" instead of "else".
Fixing this looks very promising, I've been running
8 concurrent jobs for a while now with no fatal
problems (eg many collisions, but everything recovered
and retried)

thanks,
Jacek





On 05/13/2014 09:56 PM, Serge Monkewitz wrote:
> Jacek,
>
>     Two things. First of all, notice that in :
>
>> def createIt(zk, k, v):
>>    while True:
>>        try:
>>            print "create ", v
>>            zk.create(k, v, ephemeral=True, makepath=True)
>>        except:
>>            print "create failed"
>>            sleepABit()
>>        finally:
>>            print "create ok"
>>            return
>
> your loop will only ever execute once (since the finally clause is
> executed no matter what). So you will return immediately if the creation
> fails (and yet still print “create ok”). You probably meant to use a
> try/except/else construct rather than try/except/finally?
>
> Anyway, the consequence of that is that your code then admits the
> following sequence of events:
>
>    Process A          | Process B
>    ===================| ==================
> 1.                   | createIt (fails)
> 2. delete (success)  |
> 3. createIt (success)|
> 4.                   | delete (success)
> 5.                   | createIt (success)
> 6. get (value from B)|
> 7.                   | delete (success)
> 8. delete (failure)  |
> which seems to be what you are observing in your log (process A).
>
> Either create needs to wait indefinitely for success, or you need to
> make sure not to delete k if you didn’t successfully create it.
>
> Cheers,
> Serge
>

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