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From Ted Ross <tr...@redhat.com>
Subject Re: C++ API Next Receiver Questions
Date Thu, 14 Jul 2016 17:25:55 GMT


On 07/14/2016 12:22 PM, Flores, Paul A. wrote:
> Hi,
>
>
>
> At client.
>
>
>
> Basic questions that I have answered but want to double check.
>
>
>
> Can I get some verification/clarification.
>
>
>
> How does pre-fetch influence these questions/answers?
>
>
>
> Thanks for the feedback it is appreciated.
>
>
>
> Paul
>
>
>
> Premise:
>
> Given:
>
>     a Connection with a Session. (Connection to Session 1:1?)
>
>     a Session with more than 1 Receiver. (Session to Receiver 1:N)
>
>     Default configuration specifying pre-fetch
>
>     Each Receiver has a queue. (Receiver to Queue 1:1)
>
>
>
> Questions:
>
> 1) Does Next Receiver "cycle" through receivers?
>
>     Given:
>
>         Three Receivers: A,B and C
>
>         Receivers A and C have message on their respective queues (Alpha and Charlie
respectively)
>
> After a fetch on Receiver A (messages remain on Alpha)
>
> Will a call to Next Receiver return Receiver C?

NextReceiver is not directly concerned with whether there are messages 
on the queue, but whether there are messages that have been delivered on 
the receiver to the client (based on prefetch).  So, yes, NextReceiver 
will eventually return C even though messages remain on Alpha.

>
>
>
> 2) Does Next Receiver always return the Receiver with messages on its queue?
>
>     Given:
>
>         Three Receivers: A,B and C
>
>         Receiver B's queue (Bravo) has messages while the other Receiver queues are empty
>
> After a fetch on Receiver B (messages remain on Bravo)
>
> Will a call to Next Receiver return Receiver B?

NextReceiver _only_ returns receivers on which messages have been 
prefetched.  So, yes, NextReceiver will return B in this case.  Once all 
the messages on Bravo are delivered (even if they remain), NextReceiver 
will block because there is no receiver with prefetched deliveries to 
return.

Note that if there is no prefetch on any of the receivers, NextReceiver 
will never return a receiver.

>
>
>
>
>
>
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>
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