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On 09/18/2014 05:42 PM, Steve Lewis wrote:
> On September 18, 2014 7:45 AM, Flavio Percoco wrote:
> 
>> On 09/18/2014 04:09 PM, Gordon Sim wrote:
>>
>>> However, as far as consuming messages is concerned, it can
>>> guarantee once-and-only-once and/or at-least-once delivery depending on
>>> the message pattern used to consume messages. Using pop or claims
>>> guarantees the former whereas streaming messages out of Zaqar guarantees
>>> the later.
>>>
>>> From what I can see, pop provides unreliable delivery (i.e. its similar
>>> to no-ack). If the delete call using pop fails while sending back the
>>> response, the messages are removed but didn't get to the client.
>>
>> Correct, pop works like no-ack. If you want to have pop+ack, it is
>> possible to claim just 1 message and then delete it.
> 
> Having some experience using SQS I would expect that there would be a mode
> something like what SQS provides where a message gets picked up by one 
> consumer (let's say by short-polling) and is hidden for a timeout duration from 
> other consumers, so that the consumer has time to ack. Is that how you are 
> using the term 'claim' in this case?

Correct, that's the name of the feature in Zaqar. You can find a bit of
extra information here[0]. Hope this helps.

[0] https://wiki.openstack.org/wiki/Zaqar/specs/api/v1.1#Claims

Cheers,
Flavio

-- 
@flaper87
Flavio Percoco