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From Valentin Kulichenko <valentin.kuliche...@gmail.com>
Subject Re: Timeout for ordered message
Date Tue, 10 Jan 2017 20:36:54 GMT
Yakov,

I was actually asking about the public API for messaging
(IgniteMessaging#sendOrdered
method). Here is the JavaDoc:

 * The {@code timeout} parameter specifies how long an out-of-order message
will stay in a queue,
 * waiting for messages that are ordered ahead of it to arrive. If timeout
expires, then all ordered
 * messages that have not arrived before this message will be skipped. When
(and if) expired messages
 * actually do arrive, they will be ignored.

I remember that we indeed had this scenario possible a while ago, but then
implementation of ordered messaging was reworked and 'out-of-order message'
can't happen anymore. Is this correct? If so, I think the timeout should be
removed from the API.

-Val

On Tue, Jan 10, 2017 at 2:34 AM, Yakov Zhdanov <yzhdanov@gridgain.com>
wrote:

> Val, timeout still makes sense for task sessions. It is possible that all
> jobs mapped to node have been completed, but node still receives
> attributes. Attributes are sent in ordered messages. It may happen so that
> node may start processing jobs for that task again and this way all the
> attributes will be available. If task timeout elapses then messages get
> cleared. Please let me know if you still have questions.
>
> Thanks!
> --
> Yakov Zhdanov, Director R&D
> *GridGain Systems*
> www.gridgain.com
>
> 2017-01-06 1:02 GMT+03:00 Valentin Kulichenko <
> valentin.kulichenko@gmail.com
> >:
>
> > Folks,
> >
> > Anyone knows what is the purpose of the timeout for
> > IgniteMessaging#sendOrdered method?
> >
> > void sendOrdered(@Nullable Object topic, Object msg, long timeout);
> >
> > It seems to me that in current implementation messages are always ordered
> > on communication level. I.e. if you send messages 1, 2 and 3, there is no
> > way to receive 3 before 2. The only difference between ordered and
> > unordered messages is that ordered are processed one after another in a
> > single thread, while unordered can be processed in parallel.
> >
> > Having said that, timeout for ordered messages doesn't make much sense to
> > me. Is there a scenario that I'm missing?
> >
> > -Val
> >
>

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