I just have a hard time understanding how an RMD can require an RMS
to have persistence.  Seems like that's under the RMS/client-app's
control - not the server/RMD.  How does the RMD check this?

thanks
-Doug
______________________________________________________
STSM  |  Web Services Architect  |  IBM Software Group
(919) 254-6905  |  IBM T/L 444-6905  |  [EMAIL PROTECTED]



"Paul Fremantle" <[EMAIL PROTECTED]> 
06/23/2008 05:39 PM

To
"David Illsley" <[EMAIL PROTECTED]>
cc
[email protected]
Subject
Re: Policy or other extensions to indicate persistent messaging






David

I agree with your scenarios. I do also have another angle on it, which
is really orthogonal to the actual technical scenarios:

The aspect I'm thinking of is to be able to counter people who say
that RM does not "do" persistence, and I think to be able to get
around the misinformation that has been around I think it will be
important to have an *option* to enforce persistence.

Paul



On Mon, Jun 23, 2008 at 3:57 PM, David Illsley <[EMAIL PROTECTED]> 
wrote:
> Doug,
> There are 2 drivers of this for me, both of which became apparent
> trying to explain RM to MQ centric people.
>
> 1. A desire on the client application developer's part to have a
> reasonable expectation that a one-way message will be processed.
>
> 2. A desire on a server administrators part that the sequences it is
> managing in a persistent way will be completed. It's probably a very
> expensive operation to administratively deal with a hung sequence. A
> server administrator might well wish to limit interaction to parties
> which support persistence and which can therefore recover from
> serious* failures and complete and close out sequences on their own
> without human intervention.
>
> Paul, do you have other drivers for this?
>
> David
>
> * Clearly something less serious than an asteroid taking out the data
> center hosting your servers.
>
> On Fri, Jun 20, 2008 at 6:22 PM, Doug Davis <[EMAIL PROTECTED]> wrote:
>>
>> Is thispolicy/extension thing used just for advertisement or something 
else?
>> Typically what an endpoint does internally is its own concern. However, 
I
>> can see
>> choosing one RMD over another based on whether it has a higher degree 
of
>> QoS/persistence.  But this almost sounds like you're suggesting that 
the RMD
>> tell
>> the RMS which kind of persistence it must have - which is odd to me.
>>
>> thanks
>> -Doug
>> ______________________________________________________
>> STSM  |  Web Services Architect  |  IBM Software Group
>> (919) 254-6905  |  IBM T/L 444-6905  |  [EMAIL PROTECTED]
>>
>>
>> "Paul Fremantle" <[EMAIL PROTECTED]>
>>
>> 06/20/2008 12:46 PM
>>
>> To
>> "David Illsley" <[EMAIL PROTECTED]>
>> cc
>> [email protected]
>> Subject
>> Re: Policy or other extensions to indicate persistent messaging
>>
>>
>>
>>
>> David
>>
>> Thanks for the reply.
>>
>> 1. I hope it won't be too difficult defining the details!!! But I'm
>> always an optimist.
>> 2. I agree, Open Standards != Open Source, and I presumed that it was
>> better to try out some implementation thoughts before taking this to a
>> standards process. However, if there is a feeling that this should be
>> done in a standards body, we could move it there. My own feeling
>> though is that WS-RX is in quiescent mode and so there will be inertia
>> to be overcome to get an active discussion there.
>> 3. Actually, you've asked the really tough question (how to define
>> persistent storage), which is one of the main reasons the WSRX TC
>> decided not to pursue this. However, I'm not convinced we need to. I
>> think the prime example of this is the XA spec, which is the bedrock
>> of transaction systems. If you look at the XA transaction spec, they
>> simply talk about "stable storage" with no definition. And I'm not
>> expecting this to be a legally binding policy (if such a thing
>> exists).
>>
>> Paul
>>
>> On Fri, Jun 20, 2008 at 5:11 PM, David Illsley <[EMAIL PROTECTED]>
>> wrote:
>>> This does seem like something that could be useful, though I'd imagine
>>> it'll be fraught with difficulties in defining the details.
>>>
>>> Clearly open standards!=open source, so if we come up with something,
>>> finding a standards venue would be a good next step... but that's a
>>> bit in the future.
>>>
>>> I think both parts of your proposal would be needed... a first
>>> question if you will....
>>>   Any idea on how we define 'persistent'? This must have been gone
>>> over lots by other groups that I haven't been involved in.
>>>
>>> David
>>>
>>> On Mon, Jun 16, 2008 at 11:26 AM, Paul Fremantle <[EMAIL PROTECTED]> 
wrote:
>>>> One issue that the WSRX technical committee didn't address in the
>>>> specification is the persistence of messages. Now, while there were
>>>> possibly good arguments why that was the case, the reality is that
>>>> many people want and expect WSRM to provide persistence, and 
certainly
>>>> in the case of Sandesha it does. I have long thought that there 
should
>>>> be an extension that can be used to signify whether persistence is
>>>> available and whether it is to be used. This kind of thing is 
actually
>>>> common in messaging systems and is available in other messaging specs
>>>> such as AMQP.
>>>>
>>>> This isn't at all fully baked, but the sort of thing I am thinking of 
is:
>>>>
>>>> 1) A policy element to indicate whether this endpoint supports and/or
>>>> requires persistence
>>>> 2) An exchange that happens at create sequence time that indicates
>>>> whether this sequence should/must be persistent
>>>>
>>>> Some questions:
>>>> * What do people think about this? Is anyone *against* defining this?
>>>> * If we define this, should we try to standardize it somewhere? Or
>>>> just treat is as an optional extension.
>>>> * Any comments on the approach - or suggestions for the actual XML?
>>>>
>>>> Regards,
>>>> Paul
>>>>
>>>> --
>>>> Paul Fremantle
>>>> Co-Founder and CTO, WSO2
>>>> Apache Synapse PMC Chair
>>>> OASIS WS-RX TC Co-chair
>>>>
>>>> blog: http://pzf.fremantle.org
>>>> [EMAIL PROTECTED]
>>>>
>>>> "Oxygenating the Web Service Platform", www.wso2.com
>>>>
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>>>>
>>>
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>>>
>>
>>
>>
>> --
>> Paul Fremantle
>> Co-Founder and CTO, WSO2
>> Apache Synapse PMC Chair
>> OASIS WS-RX TC Co-chair
>>
>> blog: http://pzf.fremantle.org
>> [EMAIL PROTECTED]
>>
>> "Oxygenating the Web Service Platform", www.wso2.com
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [EMAIL PROTECTED]
>> For additional commands, e-mail: [EMAIL PROTECTED]
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>>
>>
>
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>



-- 
Paul Fremantle
Co-Founder and CTO, WSO2
Apache Synapse PMC Chair
OASIS WS-RX TC Co-chair

blog: http://pzf.fremantle.org
[EMAIL PROTECTED]

"Oxygenating the Web Service Platform", www.wso2.com

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