Re: [ws-rx] [NEW ISSUE]: No mechanisms to convey that messages shouldbe polled.

[Paul Fremantle <paul@wso2.com>]

Anish

I like the idea. However, can I propose a simplification.

I suggest that we simply allow an RMS to add a header

<wsrm:MessagePending>

to any message targeted at the sequence to indicate there is a message 
that could be polled for. I propose this should be optional (even if 
there is a message pending), but recommended.

Paul




Anish Karmarkar wrote:
> Title: Polling mechanism does not provide a way for the RMS to let the 
> RMD know that there are pending messages that should be polled.
>
> Description/justification:
>
> We have a polling mechanism that allows messages to be polled. This is 
> quite helpful for RMDs that are behind the firewall. But there is no 
> mechanism for the RMS to let the RMD know that there are messages that 
> the RMD should poll for. I.e., unless the RMD polls for a message, it 
> will not know whether it should have polled!
>
> Having a mechanism for the RMS to let the RMD know that there are 
> pending messages is helpful in at least two scenarios:
>
> 1) RMD just polled for a message (perhaps because it periodically does 
> that), and would like to know if it should poll again because there 
> are additional pending messages. The RMD wants to minimize message 
> delivery delays, but the only way to do that is to increase the 
> polling period, which can result in unnecessary 
> sending/receiving/processing of messages. Given that the RMD has 
> already polled for a message, it is extremely convenient (with a 
> minimal cost) to allow the RMS to inform the RMD that there are 
> additional message waiting.
>
> 2) The RMD and RMS have ongoing communication (not necessarily a 
> wsrm:MakeConnection), it is advantageous for the RMD to let the RMS 
> know that there are pending messages by allowing the pending status to 
> be piggy-backed on ongoing communication messages.
>
> Core: core
>
> Type: design
>
> Proposal:
>
> Outline of the proposal --
> Allow two new headers wsrm:MessageStatusRequested and 
> wsrm:MessageStatus, which can be piggybacked on other messages, that 
> query and convey that there are pending messages.
>
> <wsrm:MessageStatusRequested  ...>
>   [<wsrm:Identifier> xs:anyURI </wsrm:Identifier>]?
>   [<wsrm:Address> xs:anyURI </wsrm:Address>]?
>   ...
> </wsrm:MessageStatusRequested>
>
> <wsrm:MessageStatus pending="xs:boolean" ...>
>   [<wsrm:Identifier> xs:anyURI </wsrm:Identifier>]?
>   [<wsrm:Address> xs:anyURI </wsrm:Address>]?
>   ...
> </wsrm:MessageStatus>
>
>
> -Anish


-- 

Paul Fremantle
VP/Technology, WSO2 and OASIS WS-RX TC Co-chair

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paul@wso2.com

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