Using WS-AtomicTransaction you wrap 3 SOAP-based Web services in a single transaction. When it is time to vote on the outcome of the transaction, 2 of the services vote to commit the changes made…

Question

Options

• AThe changes are committed because the transaction is considered successful as long as no
• BThe changes are rolled back because the transaction is considered unsuccessful when there is a
• CThe changes are committed because the transaction is considered successful as long as one
• DThe changes are aborted because a transaction can only be considered successful when more

• A
  5% (1)
• B
  74% (14)
• C
  16% (3)
• D
  5% (1)

Explanation

Option B is correct because WS-AtomicTransaction uses the Two-Phase Commit (2PC) protocol, which requires unanimous agreement from all participants to commit. A missing vote is treated the same as an explicit abort - the coordinator cannot assume success without hearing from every participant, so it rolls back all changes across all services to preserve atomicity ("all or nothing").

Why the distractors are wrong:

• A is wrong because it implies silence is acceptable as long as no one actively refuses - but 2PC treats no response as a failure, not a neutral non-vote.
• C is wrong because it suggests a single "yes" vote is sufficient - 2PC requires every participant to confirm readiness, not just one.
• D is wrong because it implies a majority-voting rule - 2PC is not a democracy; it requires 100% commitment, not a simple majority.

Memory tip: Think of WS-AtomicTransaction like a jury verdict - it must be unanimous. If even one juror goes silent (let alone votes "no"), the case is a mistrial and everything resets. "All commit or all rollback, no exceptions."

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