Understanding the Two-Phase Commit (2PC) Protocol in Distributed Systems

Learn how the Two-Phase Commit (2PC) protocol ensures reliable transactions in distributed systems.

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The Two-Phase Commit (2PC) protocol is used to ensure all-or-nothing outcomes in distributed systems. In Phase 1 (Preparation), the coordinator sends a 'prepare' request to all participants. Each participant votes Yes or No. In Phase 2 (Commit), if all votes are Yes, the coordinator sends a 'commit' command; otherwise, it sends a 'rollback' command. This guarantees consistency and reliability in transactions, even across multiple systems.

FAQs & Answers

  1. What is the purpose of the Two-Phase Commit (2PC) protocol? The purpose of the Two-Phase Commit (2PC) protocol is to ensure all participants in a distributed transaction either commit or abort to maintain data consistency.
  2. How does the 2PC protocol guarantee reliability? The 2PC protocol guarantees reliability by coordinating votes from all participants before finalizing a commit, ensuring that all systems are in sync.
  3. What happens if a participant votes 'No' in the 2PC process? If a participant votes 'No', the coordinator sends a 'rollback' command to all participants, aborting the transaction to maintain consistency.
  4. Where is the 2PC protocol commonly used? The 2PC protocol is commonly used in distributed databases and systems where transactions span multiple nodes, requiring coordinated commitment.