[rabbitmq-discuss] Strategy for consuming queues and ordering

[Alfonso Pantoja]

Thank you Robby and Bryan for you answers.

In my case the requirement  is to update a user connection status in
the database (online/offline). We started to use the Timestamp header
of  AMQP and I think that if comparing that timestamp with a timestamp
stored in the database is safe enough in case of the messages don't
arrive in the expected order.
In this situation I suppose the most critical point is not to loose
any message (in other words it wouldn't be acceptable a user would be
offline due to a online message had lost)


Regards,

Alfonso



2011/2/11 Bryan Murphy <bmurphy1976 at gmail.com>:
> On Thu, Feb 10, 2011 at 3:55 AM, Robert Raschke <rtrlists at googlemail.com> wrote:
>>> Can anyone tell me how to deal with queues that contain messages that
>>> are higly recommended by business logic to be ordered?
>
> snip
>
>> Whenever I hear about the problem of the required order of messages having
>> to be preserved, I start to wonder if the problem at hand is really best
>> suited to messaging. Could it be that you might be better served by
>> something like a (normal) work queue?
>>
>> If you require things to be done in a certain order, then you need to have a
>> place to actually keep them in that order. Messaging isn't the place to do
>> this.
>
> I agree.  If it needs to absolutely be in order, we put the message in
> a database transactionally and then send a "hey something changed go
> look at the database" message.
>
> Bryan
>