[rabbitmq-discuss] Messages Timeout in Queue

[Alexis Richardson]

Gagan

As I understood from your document:

a) when the User A is not logged into server 1 or server 2, any
messages sent to them by User B are discarded
b) but, when User A is logged in to server 1, any messages sent by
User B that may be routed to User A are queued in Queue A, and then
...
c) .... delivered when User A logs into server 2.

Provided that you can implement this efficiently (see other email)
then the consumer at User A only needs to discard messages that are
older than one minute, and that were not already discarded due to (a)
above.  So unless the time interval between A logging into server 1,
and A logging into server 2, is "quite long" then the 'timestamp'
method adds very little overhead.

Is that correct or have I missed something?

alexis






On Sat, Jul 4, 2009 at 8:28 PM, GAGAN ARORA<gaganarora.itm at gmail.com> wrote:
> Hi Alexis
>
> My system is similar to an IM system and is using RabbitMQ for presence
> updates and have designed it in such a way that a consumer subscribes to a
> queue only when it comes online.Now the issue is as stated by you there will
> be a large no of messages ready to be deleivered when a user comes online.
> Checking timestamp for each message will result in high cost.
>
> There can be a solution in which a message can be published using immediate
> flag. But it is desired by consumer to get all messages which are less than
> 1 minute old.
>
> Can you suggest some other solution for achieving this?
>
> Thanks
> Gagan Arora
>
>
>
>
> On Sat, Jul 4, 2009 at 3:32 PM, Alexis Richardson
> <alexis.richardson at gmail.com> wrote:
>>
>> Gagan,
>>
>> On Fri, Jul 3, 2009 at 5:08 PM, GAGAN ARORA<gaganarora.itm at gmail.com>
>> wrote:
>> > Hi Alexis
>> > The problem statement here is I dont want my messages in queue for more
>> > than
>> > 1 minute.
>>
>> The easiest way to do this is for the client to keep consuming the
>> messages from the queue.
>>
>> However: presumably you want messages to be ignored in the case where
>> (a) there is no consumer to get the messages from the queue; and (b)
>> the messages are more than one minute old.
>>
>> If so then: Have you considered putting a timestamp on the messages?
>> That way, when a consumer starts taking messages from the queue, it
>> can simply check the timestamps and throw away anything 'old'.  This
>> solution works just fine when (i) you don't need real time accuracy
>> ie. "about a minute" is just as good as "exactly a minute", and
>> provided that (ii) there aren't too many messages to throw away.
>> Judging by the document that you sent, both (i) and (ii) are true.
>>
>> Does this help?
>>
>> alexis
>>
>>
>> > I have tried expiration property while publishing a message but
>> > later came to know that it is still not implemented. Can you help me out
>> > in
>> > figuring some alternate approach?
>> > Thanks
>> > Gagan Arora
>> >
>> > On Fri, Jul 3, 2009 at 8:17 PM, Alexis Richardson
>> > <alexis.richardson at gmail.com> wrote:
>> >>
>> >> Gagan,
>> >>
>> >> On Fri, Jul 3, 2009 at 3:10 PM, GAGAN ARORA<gaganarora.itm at gmail.com>
>> >> wrote:
>> >> > Hi
>> >> > Is it possible to set message time out in Java client API, so that
>> >> > messages
>> >> > drop out from queue after some interval of time if nobody consumes
>> >> > it?.
>> >>
>> >> Not yet but this is a feature have been asking for quite a bit.  It's
>> >> on our roadmap.
>> >>
>> >> There may be other ways to achieve what you want.
>> >>
>> >> alexis
>> >>
>> >>
>> >>
>> >> > Thanks
>> >> > Gagan Arora
>> >> > _______________________________________________
>> >> > rabbitmq-discuss mailing list
>> >> > rabbitmq-discuss at lists.rabbitmq.com
>> >> > http://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
>> >> >
>> >> >
>> >
>> >
>
>