WS-Transaction Specification Released

WS-Transaction is a newly released specification, developed by Microsoft, IBM, and BEA, that defines how Web services coordinate their activities in order to ensure the integrity of underlying database operations. WS-Transaction defines two models for transactions over Web services: atomic transactions for those cases where the highest level of protection is required; and business activity transactions in which using a lower level of protection offers better scalability.

Atomic Transactions Offer Strongest Protection

WS-Transaction supports atomic (all-or-nothing) transactions in which a coordinator queries each participant in the transaction to find out if they are capable of processing the update. Each participant typically locks any database records involved in the transaction to prevent any changes from being made to the data while the transaction is being processed. Only when all participants have indicated a readiness to commit does the coordinator instruct them to make the changes. If any participant either vetoes the transaction or fails to respond, the coordinator instructs all participants to abort the transaction and discard any changes. This process is typically known as “two-phase commit” (or 2PC) and is widely used in products such as Microsoft’s Distributed Transaction Coordinator (DTC) and IBM’s CICS.