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Subject: RE: [wsbpel] Topics for the "Review input from TC members" session of the F2FSome
+1 I'm sure with WS-Reliability, WS-ReliableMessaging and a host of other specifications that will eventually become standards, there'll be enough to leverage in a fully-formed Web services architecture. There's enough work within BPEL as it currently stands without having to define the entire deployment environment on which it must work. Mark. >===== Original Message From "Satish Thatte" <satisht@microsoft.com> ===== >I think Fred's approach makes a lot of sense. It promotes a separation >of concerns between business process logic and reliability >infrastructure which makes everyone's job easier. B2B business >protocols (e.g. RosettaNet PIPs) have historically tried to build >reliability into the application protocol because they couldn't count on >anything else to provide reliability, but we should take advantage of >the opportunity in the web services space to solve the reliability >problem separately and therefore more generally for all web services to >use, not just BPEL processes. > >Satish > >-----Original Message----- >From: Marin, Mike [mailto:MMarin@filenet.com] >Sent: Friday, May 23, 2003 9:02 AM >To: Dieter Roller >Cc: wsbpel@lists.oasis-open.org >Subject: RE: [wsbpel] Topics for the "Review input from TC members" >session of the F2FSome > > >Well, yes and no. It is not a problem for stateless idempotent WSDL >operations. However, the whole point of BPEL is to support state full >and potentially long running services to run real business stuff. >Therefore, BPEL should suggest a solution or at least identify the >problem for somebody to solve. There are several solutions to this >issue, including the one mentioned by Fred (except that it does not work >under the common case of SOAP under WSDL). Others include simple >variations of two-phase commit to guarantee message delivery. > >-- >Regards, >Mike Marin > >-----Original Message----- >From: Dieter Roller [mailto:ROL@de.ibm.com] >Sent: Thursday, May 22, 2003 9:12 PM >To: Marin, Mike >Cc: wsbpel@lists.oasis-open.org >Subject: RE: [wsbpel] Topics for the "Review input from TC members" >session of the F2FSome > > >Mike, > >I don't consider this a BPEL problem; this applies to any web service. > >Cheers, > >dieter > >Dieter Roller >IBM Senior Technical Staff Member (STSM) >Member IBM Academy of Technology >Phone : +49-7031-164476 >Fax : +49-7031-164890 >e-mail rol@de.ibm.com > > > >|---------+----------------------------> >| | "Marin, Mike" | >| | <MMarin@filenet.c| >| | om> | >| | | >| | 05/22/2003 09:01 | >| | PM | >| | | >|---------+----------------------------> > >>----------------------------------------------------------------------- >----------------------------------------------------------------------| > | >| > | To: "Cummins, Fred A" <fred.cummins@eds.com>, ><wsbpel@lists.oasis-open.org> >| > | cc: >| > | Subject: RE: [wsbpel] Topics for the "Review input from TC >members" session of the F2FSome >| > | >| > | >| > >>----------------------------------------------------------------------- >----------------------------------------------------------------------| > > > >Fred, > >With respect to topic "a"; I agree, but how do you do that using a SOAP >binding on WSDL? (Or an HTTP binding for that matter). I think the >specification should have some wording on this topic. > >-- >Regards, >Mike Marin > >-----Original Message----- >From: Cummins, Fred A [mailto:fred.cummins@eds.com] >Sent: Thursday, May 22, 2003 11:53 AM >To: Marin, Mike; wsbpel@lists.oasis-open.org >Subject: RE: [wsbpel] Topics for the "Review input from TC members" >session of the F2FSome > >Mike, > >Such busiess operations should be implemented with reliable messaging. >Thus the individual participants employ transactions to post and >remove messages from their respective queues, and the reliable >messaging protocol assures that messages are communicated from the >sending queue to the receiving queue once and only once. In effect >the reliable messaging protocol is the "transaction" protocol of the >exchange. > >Fred Cummins >EDS > >> -----Original Message----- >> From: Marin, Mike [mailto:MMarin@filenet.com] >> Sent: Thursday, May 22, 2003 2:17 PM >> To: wsbpel@lists.oasis-open.org >> Subject: [wsbpel] Topics for the "Review input from TC >> members" session >> of the F2FSome >> >> >> >> I have few issues that I will like to add to the list of "Review input >> from TC members" for the F2F meeting. >> >> a- We don't have distributed transactions on web services yet. So how >> do we insure that an activity such as an "invoke" is executed exactly >> one time? The following example illustrates the problem: >> >> 1. Process A begins execution of an invoke instruction, and sends an >> input message to Process B. There is no output message defined on the >> invoke. >> 2. Process B is defined with a receive instruction >> corresponding to the >> invoke of process A, and the receive instruction creates a >> new instance >> of the process. So upon receipt of the message from process A, a new >> instance of process B is created, and this instance executes >> the receive >> instruction. >> 3. The machine hosting process A crashes. >> 4. Process B executes the next step, which is to debit an account and >> update a database. >> 5. Process B terminates. Process B has finished. >> 6. The machine hosting process A is restarted. Process A then >> re-executes the invoke instruction. >> >> On step 6, how can we prevent process A from executing the invoke a >> second time, creating another instance of process B, and debiting the >> account a second time? >> >> b- Invoking an operation, with input and output, that is >> implemented by >> a process using receive and replay requires the WSDL operation to be >> asynchronous. A process may take days or weeks between the receive and >> the reply, so the client cannot keep a connection open waiting for the >> reply. Although WSDL 1.1 talks about asynchronous operations; it does >> not seems to be any support for it in the WSDL specification. >> >> From the point of view of the process executing the invoke >> the operation >> is asynchronous in that the process blocks for the reply. >> But, from the >> point of view of the service implementing the receive reply pair; the >> operation is asynchronous, and there is no way to prevent the time >> between the receive and the reply from taking weeks. So, the invoking >> process is blocked, but it cannot maintain a connection open. >> >> c- I am also concerned with the use of WS-Addressing for end point >> references. I'm basically echoing the comment by Ron Ten-Hove. >> >> d- Just a note in the specification reference section, >> reference [16] is >> WS-Addressing. In appendix C, reference [16] seems to be for >> WS-Transaction. >> >> >> -- >> Mike Marin | FileNET Corporation | (714) 327-5134 >> Software Architect | 3565 Harbor Boulevard | mmarin@filenet.com >> eProcess Development | Costa Mesa, CA 92626 | mmarin@acm.org >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: wsbpel-unsubscribe@lists.oasis-open.org >> For additional commands, e-mail: wsbpel-help@lists.oasis-open.org >> > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: wsbpel-unsubscribe@lists.oasis-open.org >For additional commands, e-mail: wsbpel-help@lists.oasis-open.org > > > > > > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: wsbpel-unsubscribe@lists.oasis-open.org >For additional commands, e-mail: wsbpel-help@lists.oasis-open.org > > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: wsbpel-unsubscribe@lists.oasis-open.org >For additional commands, e-mail: wsbpel-help@lists.oasis-open.org
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