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Subject: RE: [ws-rx] New PR Issue: RMD cannot detect some incomplete Sequences
I'm ok with this suggestion. What do other people think? - gp > -----Original Message----- > From: Paul Fremantle [mailto:paul@wso2.com] > Sent: Saturday, October 21, 2006 1:02 AM > To: Gilbert Pilz > Cc: ws-rx@lists.oasis-open.org > Subject: Re: [ws-rx] New PR Issue: RMD cannot detect some > incomplete Sequences > > Gil > > In your example, if we add the LastMessage marker back, the > RMD will know that there is an incomplete sequence. But it > won't know how many messages are missing. It could be 9 and > 10, or it could be a million messages, because the > LastMessage didn't get through. > > So instead, I would suggest we add a HighestMessageNumber to > the CloseSequence and TerminateSequence requests. That way > the RMD has exact knowledge of which messages are missing. > > Paul > > Gilbert Pilz wrote: > > > > *Title*: RMD cannot detect some incomplete Sequences > > > > *Description*: > > > > WS-RM 1.0 [1] defined a sub-element of the > wsrm:Sequence header > > that served to mark the containing message as the last message > > in a Sequence. WS-RM 1.1 [2] has removed this element. > > Consequently the RMD has no guaranteed way of determining > > whether it has received all the messages in a Sequence. This > > presents obvious drawbacks to an Application Destination that > > may wish to know if it has received all the data that the > > Application Source sent it. In addition to this it makes > > correctly implementing the "incomplete sequence behavior" > > semantics impossible since the RMD cannot always > determine what > > is and isn't an "incomplete Sequence". > > > > For example, suppose an RMS creates a Sequence, sends messages > > 1-10, then sends a CloseSequence. Suppose that > messages 9 and 10 > > get lost but the CloseSequence message is received by the RMD. > > The RMS can determine that the Sequence is incomplete > (final ack > > is missing 9 and 10 from the range), but the RMD has no way of > > knowing, nor is there any way for it to discover, that the > > Sequence is incomplete. If the IncompleteSequenceBehavior was > > "DiscardEntireSequence" then the RMS will conclude that all of > > the messages will be discarded whereas the RMD will, in all > > likelihood, deliver all of the messages to the Application > > Destination under the assumption that the Sequence is > complete. > > > > *Proposal*: > > > > Put the LastMessage element back in the Sequence element. Add > > additional wording around the definition of > > IncompleteSequenceBehavior stating that a Sequence without a > > message that was marked "last" is defined as incomplete. > > > > *References*: > > > > [1] > > > _http://specs.xmlsoap.org/ws/2005/02/rm/ws-reliablemessaging.pdf_ > > [2] > > > > > _http://docs.oasis-open.org/ws-rx/wsrm/200608/wsrm-1.1-spec-cd-04.pdf_ > > > > > > -- > Paul Fremantle > VP/Technology and Partnerships, WSO2 > OASIS WS-RX TC Co-chair > > http://bloglines.com/blog/paulfremantle > paul@wso2.com > (646) 290 8050 > > "Oxygenating the Web Service Platform", www.wso2.com > > >
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