Transcript Advances in WS-Transaction and WS

Advances in
WS-Transaction and
WS-Coordination
William Cox, Ph.D.
OASIS Symposium on Reliable Infrastructure
New Orleans
26 April 2004
Outline
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Motivation and History
The Specifications
Evolution
Specification Techniques
Comparisons
Standardization Issues
Future
Summary and References
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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
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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
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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)
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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
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Specification Relationships
v1.1
v1.0
WSAtomicTransaction
WSBusinessActivity
WS-Transaction
WS-Coordination
WS-Coordination
WS-Addressing
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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
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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
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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
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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
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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)
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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
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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
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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
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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
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References
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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 Links
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnglobspec/html/wsatspecindex.asp
• BEA Links
http://dev2dev.bea.com/technologies/webservices/standards.jsp
Interoperability and Feedback
http://www-106.ibm.com/developerworks/offers/WS-Specworkshops/ws-tx200402post.html
http://msdn.microsoft.com/webservices/community/workshops/transactionws032004.aspx
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References (continued)
• WS-CAF (Arjuna, Fujitsu, Iona, Oracle, Sun) July 2003,
OASIS TC
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http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-caf
• BTP OASIS TC
http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=business-transaction
– BTP 1.0
http://www.oasis-open.org/committees/download.php/1184/2002-06-03.BTP_cttee_spec_1.0.pdf
– BTP Primer
http://www.oasis-open.org/committees/download.php/2077/BTP_Primer_v1.0.20020605.pdf
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