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From "Flores, Paul A." <PAUL.A.FLO...@SAIC.COM>
Subject RE: C++ API Next Receiver Questions- More
Date Thu, 14 Jul 2016 17:55:31 GMT
Ted,

Thanks for the reply.

Paul


Questions remain.

In the C++ API documentation it is unclear how to set up prefetching.  Is it related to setting
the receiver capacity?  Is there an example?

With prefetch setup does a fetch return more than one message at a time from a specific queue?

________________________________________
From: Ted Ross [tross@redhat.com]
Sent: Thursday, July 14, 2016 12:25 PM
To: users@qpid.apache.org
Subject: Re: C++ API Next Receiver Questions

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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that further dissemination, distribution, use or copying of this communication is strictly
prohibited. Anyone who received this message in error should notify the sender immediately
by telephone or by return email and delete it from his or her computer.
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