ebxml-msg — archive

RE: T2 Retry with Delivery Receipt

From: System
To: [email protected]
Date: Fri, 14 Sep 2001 10:03:00 -0000

David, There have been 50 years of development of disaster backup and recovery scenarios and software that have the answers to many of these questions. Regarding MSH2 catching fire, the answer is easy. If MSH2 catches fire, APP2 will be aware of it; an application should not commit the transaction resulting from a message if it cannot send the delivery receipt or reply. Thus APP2 should discard the message and roll back anything it did. If the reliable message had not yet been acknowledged when the plane crashed into MSH2, and if it's the A-MSH's job to recognize delivery failure and notify the A application, all is well. If the message had successfully been acknowledged, the A application will never receive the response and someone will have to make a phone call to resolve the in-doubt situation. Regards, Marty ************************************************************************************* Martin W. Sachs IBM T. J. Watson Research Center P. O. B. 704 Yorktown Hts, NY 10598 914-784-7287; IBM tie line 863-7287 Notes address: Martin W Sachs/Watson/IBM Internet address: mwsachs @ us.ibm.com ************************************************************************************* "Burdett, David" <[email protected]> on 09/13/2001 05:16:57 PM To: "'Dan Weinreb'" <[email protected]>, Martin W Sachs/Watson/IBM@IBMUS cc: [email protected] Subject: RE: T2 Retry with Delivery Receipt Dan You wanted a use case where where you have an IM "that's unreliable but must act at the ebXML MS level of abstrction, i.e. it understands and interprets the data formats described in the MS spec". In my last email at (http://lists.oasis-open.org/archives/ebxml-msg/200109/msg00191.html) I explained the benefits of an ebXML MSH and included the following diagram: A -------------- BM ------ B1 ------- B MSH MSH MSH APP1 | | -------- B2 ------- B | MSH APP2 | ----- Inteface ---- B App APP3 Suppose the B2 MSH and the B APP2 are running on the same server and the server suffers a head crash. In this case the BM MSH should respond with a Delivery Failure Notification to A when A sends it a reliable message. You also cannot reasonably guarantee that the B2MSH when would NEVER lose data when it crashed. Therefore it is quite possible that a Delivery Receipt could get lost. This in fact suggests a really nasty use case. Suppose: 1. The B2 MSH forwards the message to APP2 2. The B2 MSH cathes fire and as a result loses both its database and recovery log files and so CANNOT recover the fact that it previously forwarded a message to APP2. Thoughts? David