advances in ws-transaction and ws-coordination

Advances inWS-Transaction and

WS-Coordination

William Cox, Ph.D.OASIS Symposium on Reliable Infrastructure

New Orleans

26 April 2004

Cox OASIS Symposium 20040426 2

Outline

• Motivation and History

• The Specifications

• Evolution

• Specification Techniques

• Comparisons

• Standardization Issues

• Future

• Summary and References


Disclaimer

• All opinions are those of the individual author of this presentation, and do not necessarily reflect those of the companies or individuals who are the specification authors.

• “My opinion, and welcome to it.”- apologies to James Thurber


Motivations

• Support Business process, legacy integration• Designed from the ground up as composable

Web services• Tailored to specific needs

– WS-AT – tightly coupled, legacy integration, rollback semantics

– WS-BA – loosely coupled, long running, compensation semantics

– WS-C – Factoring of context management


History

• XA (X/Open)

• OMG Object Transaction Service– And Extended Structures for OTS

• XOCP, others

• BTP (similar goals but more complex)

• WS-CAF (overlapped completion of v1.1)


Published Specifications

• August 2002 Publications– WS-Coordination 1.0– WS-Transaction 1.0 [WS-TX]

• September 2003 Publications– WS-Coordination 1.1 [WS-C]– WS-AtomicTransaction [WS-AT]

• January 2004 Publication– WS-BusinessActivity [WS-BA]

• Abbreviations– WS-Transaction [WS-TX] refers to WS-AT+WS-BA


Specification Relationships

WS-Transaction

WS-AtomicTransaction

WS-BusinessActivity

WS-Coordination

WS-Coordination

WS-Addressing

v1.0 v1.1


Structural Evolution v1.0-v1.1

• WS-AtomicTransaction and WS-BusinessActivity are now separate specifications– Were subparts of WS-TX 1.0

• Use of WS-Addressing Endpoint Reference’s opaque ReferenceProperties throughout

• Editorial and readability improvements

• Separate publication of WS-AT and WS-BA


Technical Evolution v1.0-v1.1

• General– Adopted opaque Endpoint Reference from WS-Addressing

• v1.0 “roll your own” contributed to WS-Addressing requirements

– Updated and enhanced security considerations, policy

• WS-AT– Renamed to Volatile 2PC, Durable 2PC– Complete state tables

• WS-BA– Named more consistently

• BusinessActivityWithCoordinatorCompletion• BusinessActivityWithParticipantCompletion

– Renamed some states– Complete state tables


Specification Techniques

• State reduction through simplification– Factored WS-Coordination– Didn’t try to view state of entire interaction

• Only the coordinator and participant separate views

• Some additional care for consistency designed in

– Acknowledge then ignore “state smear”

• Broad applicability for WS-Coordination– WS-AT, WS-BA, other coordinations


Some Comparisons

• WS-C/WS-TX– WS-Coordination specified as simple algorithm– WS-AT has 7 states– WS-BA has 8/9 states

• BTP has 28 Superior, 36 Inferior states– But includes ~ WS-C x WS-BA states in one

machine


Some Comparisons (continued)

• WS-CAF—Bookkeeping difficult– Builds on context mgt protocol WS-CTX, as

does WS-TX– Atomic has 8 states and 14 messages– LRA has many sub-protocols (total of 40

messages)


Another Comparison

• Pages of specification– BTP: 188 pages– WS-CAF base docs 240 pages– WS-Coordination+WS-AT+WS-BA 59 pages

• Does reflect time needed to read and understand


Standardization Issues

• Use of WS-Addressing requires standardization of at least Endpoint Reference– This is also an issue for the new WS-Resource Framework and

WS-Notification TC base documents

• Factoring useful if not overdone– WS-TX/WS-C factoring seems about right

• Specify, demonstrate interoperability, iterate– Focus on interoperable implementations important

– When and in which cycle?

– More mature specs into standardization process vs buy-in


The Future

• Author companies have committed to submitting to a standards organization

• Feedback meeting March 2004– See references

• Comment license required – So can maintain royalty-free approach to these specs

• Interoperability event in planning


Summary

• WS-Transaction and WS-Coordination simple enough, rich enough

• Composable web services target level

• Specifications at the right level– Reasonable number of states

– Reasonable number of protocols

– Comparatively lower complexity than competing specs

• Progressing to interoperability testing and submission to a standards organization


References

• WS-Coordination• WS-AtomicTransaction• WS-BusinessActivity• WS-Addressing• IBM Links

http://www-106.ibm.com/developerworks/views/webservices/standards.jsp

Alphabetization problems--some under “WS-”, some under “Web Services”

• Microsoft Linkshttp://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnglobspec/html/wsatspecindex.asp

• BEA Linkshttp://dev2dev.bea.com/technologies/webservices/standards.jsp

Interoperability and Feedbackhttp://www-106.ibm.com/developerworks/offers/WS-Specworkshops/ws-tx200402post.html

http://msdn.microsoft.com/webservices/community/workshops/transactionws032004.aspx

http://www-106.ibm.com/developerworks/views/webservices/standards.jsp

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnglobspec/html/wsatspecindex.asp

http://dev2dev.bea.com/technologies/webservices/standards.jsp


References (continued)

• WS-CAF (Arjuna, Fujitsu, Iona, Oracle, Sun) July 2003, OASIS TC

– http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-caf

• BTP OASIS TChttp://www.oasis-open.org/committees/tc_home.php?wg_abbrev=business-transaction

– BTP 1.0http://www.oasis-open.org/committees/download.php/1184/2002-06-03.BTP_cttee_spec_1.0.pdf

– BTP Primerhttp://www.oasis-open.org/committees/download.php/2077/BTP_Primer_v1.0.20020605.pdf

http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-caf

http://www.oasis-open.org/committees/download.php/2077/BTP_Primer_v1.0.20020605.pdf

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