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Posted to users@activemq.apache.org by jkurtz <jk...@gmail.com> on 2007/02/04 00:07:46 UTC
Pausing Transmission
We are interested in pausing the message transmission periodically from
outside of Active MQ, while allowing incoming messages to accumulate.
Modifying the source code is an option, and we are looking at the transport
class.
Does anyone know if this is feasible without major revisions of the code?
--
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Re: [Spam: 5.0] Pausing Transmission
Posted by James Strachan <ja...@gmail.com>.
That all sounds great - particularly the bit about contributing
changes back to the project :)
The best place to start is probably to write your own TransportFilter
to do the stuff you need (allowing pause/resume/monitor throughput etc
etc). If you need closer integration with the TCP layer you might even
wanna inherit from the TcpTransport* stuff. (e.g. you might wanna add
hooks to the TcpInputStream/TcpOuputStream to count the bytes moved
etc).
To simplify the integration; it might be easiest for each of your
custom TransportFilter implementations to lookup in JMX some
controller MBean that can be used as a single point to hold the policy
information and act as a global start/stop guage etc. (Or worst case,
a static variable :)
Please do let us know how you get on & please do submit any patches
that helps you implement this feature...
http://activemq.apache.org/contributing.html
On 3/2/07, jkurtz <jk...@gmail.com> wrote:
>
> James
>
> Again, thanks for taking the time to help. We got some feedback from the
> customer, they want to be able to do the Quality of Service measurements and
> control from outside of Active MQ. We still want to control the transport,
> turning it on and off, but we want to empower the Broker object to do this.
> However, if you can think of a better way to control transmission
> externally, please let me know.
>
> We would like to add the methods "stopTransport" and "startTransport" to the
> broker object, then modify the TcpTransportServer or other class to
> implement this. We would this to work across all connections. The QoS engine
> would then utilize an Embedded Broker application to control the message
> flow. Placing control outside of ActiveMQ allows for the measurement and Qos
> algoritms to be changed without having to modify the Active MQ source code.
>
> Any changes we make and the documentation will be released for evaluation
> and hopefully integration back into the main Active MQ branch. Adding the
> QoS capability increases the usefulness of this, as Active MQ can be used as
> a means of controlling network traffic.
>
> thanks much
>
> John
>
>
>
> ========================
>
> James.Strachan wrote:
> >
> > On 2/6/07, jkurtz <jk...@gmail.com> wrote:
> >>
> >> The reason that the dispatch needs to be paused on the Server side is for
> >> a
> >> Quality of Service Broker to control the message dispatch if the network
> >> traffic gets to be too much. This is similar to the client Pre-Fetch
> >> Limit,
> >> except the messages are measured and controlled on servicer hosting the
> >> Active MQ instance, and not the client.
> >>
> >> We want to create a server-side implementation of the prefetch limit.
> >> Instead of using the client acknowledgements to control messaging, we
> >> want
> >> to use QoS service parameters on the Server to pause the dispatch.
> >>
> >> I can provide more details if you wish.
> >
> > OK I get it now, thanks. It sounds like the best thing to do is to
> > write your own derivation of TcpTransportFactory and
> > TcpTransportServer overloading the createTransport() method as its
> > only the broker side you need to change - so that each Transport that
> > gets created for each connection to the broker gets wrapped in your
> > own TransportFilter wrapper object which does the flow control (only
> > allowing so many bytes per second or whatever). Whether you want to do
> > the flow control across all connections, or on a per connection basis
> > is your call.
> >
> > By all means ask for more help as you try to implement this (maybe
> > chatting further on dev@activemq.apache.org is better) - if you would
> > like to donate a patch we could make this a standard feature of
> > ActiveMQ. e.g. we could use a property on the TcpTransportServer to
> > indicate the throttling rate to use, which if its set we wrap the
> > TcpTransport in a throttler TransportFilter.
> >
> > --
> >
> > James
> > -------
> > http://radio.weblogs.com/0112098/
> >
> >
>
> --
> View this message in context: http://www.nabble.com/Pausing-Transmission-tf3167927s2354.html#a9270539
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>
>
--
James
-------
http://radio.weblogs.com/0112098/
Re: [Spam: 5.0] Pausing Transmission
Posted by jkurtz <jk...@gmail.com>.
James
Again, thanks for taking the time to help. We got some feedback from the
customer, they want to be able to do the Quality of Service measurements and
control from outside of Active MQ. We still want to control the transport,
turning it on and off, but we want to empower the Broker object to do this.
However, if you can think of a better way to control transmission
externally, please let me know.
We would like to add the methods "stopTransport" and "startTransport" to the
broker object, then modify the TcpTransportServer or other class to
implement this. We would this to work across all connections. The QoS engine
would then utilize an Embedded Broker application to control the message
flow. Placing control outside of ActiveMQ allows for the measurement and Qos
algoritms to be changed without having to modify the Active MQ source code.
Any changes we make and the documentation will be released for evaluation
and hopefully integration back into the main Active MQ branch. Adding the
QoS capability increases the usefulness of this, as Active MQ can be used as
a means of controlling network traffic.
thanks much
John
========================
James.Strachan wrote:
>
> On 2/6/07, jkurtz <jk...@gmail.com> wrote:
>>
>> The reason that the dispatch needs to be paused on the Server side is for
>> a
>> Quality of Service Broker to control the message dispatch if the network
>> traffic gets to be too much. This is similar to the client Pre-Fetch
>> Limit,
>> except the messages are measured and controlled on servicer hosting the
>> Active MQ instance, and not the client.
>>
>> We want to create a server-side implementation of the prefetch limit.
>> Instead of using the client acknowledgements to control messaging, we
>> want
>> to use QoS service parameters on the Server to pause the dispatch.
>>
>> I can provide more details if you wish.
>
> OK I get it now, thanks. It sounds like the best thing to do is to
> write your own derivation of TcpTransportFactory and
> TcpTransportServer overloading the createTransport() method as its
> only the broker side you need to change - so that each Transport that
> gets created for each connection to the broker gets wrapped in your
> own TransportFilter wrapper object which does the flow control (only
> allowing so many bytes per second or whatever). Whether you want to do
> the flow control across all connections, or on a per connection basis
> is your call.
>
> By all means ask for more help as you try to implement this (maybe
> chatting further on dev@activemq.apache.org is better) - if you would
> like to donate a patch we could make this a standard feature of
> ActiveMQ. e.g. we could use a property on the TcpTransportServer to
> indicate the throttling rate to use, which if its set we wrap the
> TcpTransport in a throttler TransportFilter.
>
> --
>
> James
> -------
> http://radio.weblogs.com/0112098/
>
>
--
View this message in context: http://www.nabble.com/Pausing-Transmission-tf3167927s2354.html#a9270539
Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Re: Pausing Transmission
Posted by James Strachan <ja...@gmail.com>.
On 2/6/07, jkurtz <jk...@gmail.com> wrote:
>
> The reason that the dispatch needs to be paused on the Server side is for a
> Quality of Service Broker to control the message dispatch if the network
> traffic gets to be too much. This is similar to the client Pre-Fetch Limit,
> except the messages are measured and controlled on servicer hosting the
> Active MQ instance, and not the client.
>
> We want to create a server-side implementation of the prefetch limit.
> Instead of using the client acknowledgements to control messaging, we want
> to use QoS service parameters on the Server to pause the dispatch.
>
> I can provide more details if you wish.
OK I get it now, thanks. It sounds like the best thing to do is to
write your own derivation of TcpTransportFactory and
TcpTransportServer overloading the createTransport() method as its
only the broker side you need to change - so that each Transport that
gets created for each connection to the broker gets wrapped in your
own TransportFilter wrapper object which does the flow control (only
allowing so many bytes per second or whatever). Whether you want to do
the flow control across all connections, or on a per connection basis
is your call.
By all means ask for more help as you try to implement this (maybe
chatting further on dev@activemq.apache.org is better) - if you would
like to donate a patch we could make this a standard feature of
ActiveMQ. e.g. we could use a property on the TcpTransportServer to
indicate the throttling rate to use, which if its set we wrap the
TcpTransport in a throttler TransportFilter.
--
James
-------
http://radio.weblogs.com/0112098/
Re: Pausing Transmission
Posted by jkurtz <jk...@gmail.com>.
The reason that the dispatch needs to be paused on the Server side is for a
Quality of Service Broker to control the message dispatch if the network
traffic gets to be too much. This is similar to the client Pre-Fetch Limit,
except the messages are measured and controlled on servicer hosting the
Active MQ instance, and not the client.
We want to create a server-side implementation of the prefetch limit.
Instead of using the client acknowledgements to control messaging, we want
to use QoS service parameters on the Server to pause the dispatch.
I can provide more details if you wish.
=============
James.Strachan wrote:
>
> On 2/3/07, jkurtz <jk...@gmail.com> wrote:
>> We are interested in pausing the message transmission periodically from
>> outside of Active MQ, while allowing incoming messages to accumulate.
>> Modifying the source code is an option, and we are looking at the
>> transport
>> class.
>>
>>
>> Does anyone know if this is feasible without major revisions of the code?
>
> Could you explain a little bit more as to why you want to do this?
>
> With the use of prefetch, messages are only dispatched to consumers
> when they have spare capacity anyway (so dispatching stops if a
> consumer pauses)
>
> http://activemq.apache.org/what-is-the-prefetch-limit-for.html
> --
>
> James
> -------
> http://radio.weblogs.com/0112098/
>
>
--
View this message in context: http://www.nabble.com/Pausing-Transmission-tf3167927.html#a8818110
Sent from the ActiveMQ - User mailing list archive at Nabble.com.
Re: Pausing Transmission
Posted by James Strachan <ja...@gmail.com>.
On 2/3/07, jkurtz <jk...@gmail.com> wrote:
> We are interested in pausing the message transmission periodically from
> outside of Active MQ, while allowing incoming messages to accumulate.
> Modifying the source code is an option, and we are looking at the transport
> class.
>
>
> Does anyone know if this is feasible without major revisions of the code?
Could you explain a little bit more as to why you want to do this?
With the use of prefetch, messages are only dispatched to consumers
when they have spare capacity anyway (so dispatching stops if a
consumer pauses)
http://activemq.apache.org/what-is-the-prefetch-limit-for.html
--
James
-------
http://radio.weblogs.com/0112098/