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Posted to users@qpid.apache.org by Rajesh Khan <ra...@gmail.com> on 2013/08/14 20:55:21 UTC
Any way Qpid could preserve messages in TOPICS. Possibility ?
It seems like we are running into a requirement and I wanted to know if
there was a way for TOPICS to preserve the last message Initially I was
using LVQ which was really great however due to acknowledging messages and
the delay we get because of that I moved to using QPID topics instead of
queues. Now I want to know if there is a way of preserving the last message
in a topic or if there is a way of disabling receive acknowledgment in
Queues.
Re: Initial Value Exchange, does anyone use it? (was Re: Any way
Qpid could preserve messages in TOPICS. Possibility ?)
Posted by Gordon Sim <gs...@redhat.com>.
On 10/28/2013 04:06 PM, Jakub Scholz wrote:
> Although I asked the original question two months ago, it was really only
> out of curiosity about how the topics work. I'm not using it anywhere.
Thanks Jakub, and I didn't mean to imply anything by quoting you(!).
That was just the last discussion of the feature I had in my mind.
> On Mon, Oct 28, 2013 at 4:48 PM, Gordon Sim <gs...@redhat.com> wrote:
>> Does anyone actually use the 'Initial Value Exchange' feature? In my mind
>> at least, the 'Last Value Queue' gives the same capability and more. Does
>> anyone have a use case that IVE solves but LVQ does not?
>>
>> If no one is using it and no-one has a use case that requires it, perhaps
>> it would be worth deprecating and eventually removing?
If there is anyone else with views on the feature, I'd be eager to hear
from you!
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Re: Initial Value Exchange, does anyone use it? (was Re: Any way Qpid
could preserve messages in TOPICS. Possibility ?)
Posted by Jakub Scholz <ja...@scholz.cz>.
Hi Gordon,
Although I asked the original question two months ago, it was really only
out of curiosity about how the topics work. I'm not using it anywhere.
Regards
Jakub
On Mon, Oct 28, 2013 at 4:48 PM, Gordon Sim <gs...@redhat.com> wrote:
> On 08/15/2013 01:17 PM, Gordon Sim wrote:
>
>> On 08/15/2013 01:05 PM, Jakub Scholz wrote:
>>
>>> Curious question ... would a message from an exchange configured as
>>> "Initial Value Exchange" get propagated through the topic when a new
>>> subscription is created (assuming the routing key and binding keys are a
>>> match)?
>>>
>>
>> Yes, the initial value exchange option would mean the last message sent
>> to the exchange was added to any newly bound queue.
>>
>
> Does anyone actually use the 'Initial Value Exchange' feature? In my mind
> at least, the 'Last Value Queue' gives the same capability and more. Does
> anyone have a use case that IVE solves but LVQ does not?
>
> If no one is using it and no-one has a use case that requires it, perhaps
> it would be worth deprecating and eventually removing?
>
>
>
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>
>
Initial Value Exchange, does anyone use it? (was Re: Any way Qpid
could preserve messages in TOPICS. Possibility ?)
Posted by Gordon Sim <gs...@redhat.com>.
On 08/15/2013 01:17 PM, Gordon Sim wrote:
> On 08/15/2013 01:05 PM, Jakub Scholz wrote:
>> Curious question ... would a message from an exchange configured as
>> "Initial Value Exchange" get propagated through the topic when a new
>> subscription is created (assuming the routing key and binding keys are a
>> match)?
>
> Yes, the initial value exchange option would mean the last message sent
> to the exchange was added to any newly bound queue.
Does anyone actually use the 'Initial Value Exchange' feature? In my
mind at least, the 'Last Value Queue' gives the same capability and
more. Does anyone have a use case that IVE solves but LVQ does not?
If no one is using it and no-one has a use case that requires it,
perhaps it would be worth deprecating and eventually removing?
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Re: Any way Qpid could preserve messages in TOPICS. Possibility ?
Posted by Gordon Sim <gs...@redhat.com>.
On 08/15/2013 01:05 PM, Jakub Scholz wrote:
> Curious question ... would a message from an exchange configured as
> "Initial Value Exchange" get propagated through the topic when a new
> subscription is created (assuming the routing key and binding keys are a
> match)?
Yes, the initial value exchange option would mean the last message sent
to the exchange was added to any newly bound queue.
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Re: Any way Qpid could preserve messages in TOPICS. Possibility ?
Posted by Jakub Scholz <ja...@scholz.cz>.
Hi Gordon,
Curious question ... would a message from an exchange configured as
"Initial Value Exchange" get propagated through the topic when a new
subscription is created (assuming the routing key and binding keys are a
match)?
Thanks & Regards
Jakub
On Thu, Aug 15, 2013 at 10:44 AM, Gordon Sim <gs...@redhat.com> wrote:
> On 08/14/2013 07:55 PM, Rajesh Khan wrote:
>
>> It seems like we are running into a requirement and I wanted to know if
>> there was a way for TOPICS to preserve the last message Initially I was
>> using LVQ which was really great however due to acknowledging messages and
>> the delay we get because of that I moved to using QPID topics instead of
>> queues. Now I want to know if there is a way of preserving the last
>> message
>> in a topic or if there is a way of disabling receive acknowledgment in
>> Queues.
>>
>
> The distinction between queue and topic is a slightly fuzzy one. In JMS of
> course they represent two distinct messaging patterns. In pre 1.0 AMQP,
> there is no concept of a 'topic' - generally the topic pattern as
> understood in JMS is implemented by binding a queue per subscription to an
> exchange.
>
> However, another way of getting a similar pattern is using a queue to
> which subscribers connect as 'browsers' (non-destructive, non-competing
> consumers of the messages). Used in this mode the LVQ is essentially a
> topic that retains the last message for a given key value.
>
> For browsers on a queue, the acknowledgement isn't actually needed in that
> case.
>
> For competing, i.e. destructive consumers, the acknowledgement can be
> implied meaning no explicit acknowledgement needs to be issued. To do this
> you would put 'reliability: unreliable' in your link options in the address
> with which the receiver was created.
>
> I am however curious also as to the delay you were observing. If
> acknowledging every n messages, and doing so asynchronously, I would not
> expect a very large impact on throughput and certainly no 'delay' (as I
> understand the term).
>
>
> ------------------------------**------------------------------**---------
> To unsubscribe, e-mail: users-unsubscribe@qpid.apache.**org<us...@qpid.apache.org>
> For additional commands, e-mail: users-help@qpid.apache.org
>
>
Re: Any way Qpid could preserve messages in TOPICS. Possibility ?
Posted by Gordon Sim <gs...@redhat.com>.
On 08/14/2013 07:55 PM, Rajesh Khan wrote:
> It seems like we are running into a requirement and I wanted to know if
> there was a way for TOPICS to preserve the last message Initially I was
> using LVQ which was really great however due to acknowledging messages and
> the delay we get because of that I moved to using QPID topics instead of
> queues. Now I want to know if there is a way of preserving the last message
> in a topic or if there is a way of disabling receive acknowledgment in
> Queues.
The distinction between queue and topic is a slightly fuzzy one. In JMS
of course they represent two distinct messaging patterns. In pre 1.0
AMQP, there is no concept of a 'topic' - generally the topic pattern as
understood in JMS is implemented by binding a queue per subscription to
an exchange.
However, another way of getting a similar pattern is using a queue to
which subscribers connect as 'browsers' (non-destructive, non-competing
consumers of the messages). Used in this mode the LVQ is essentially a
topic that retains the last message for a given key value.
For browsers on a queue, the acknowledgement isn't actually needed in
that case.
For competing, i.e. destructive consumers, the acknowledgement can be
implied meaning no explicit acknowledgement needs to be issued. To do
this you would put 'reliability: unreliable' in your link options in the
address with which the receiver was created.
I am however curious also as to the delay you were observing. If
acknowledging every n messages, and doing so asynchronously, I would not
expect a very large impact on throughput and certainly no 'delay' (as I
understand the term).
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