Explain the two-phase transaction confirmation process in distributed systems.

The Two-Phase Commit (2PC) process is a protocol that ensures transaction atomicity in distributed systems.

Working principle:

1. Prepare phase:

   • The transaction coordinator sends a prepare request to all participants.
   • Each participant performs a local transaction and reports to the coordinator whether it is ready to commit (vote commit) or abort (vote abort).

2. Commit phase:

   • If all participants are ready, the coordinator sends a commit command, and all participants record the changes.
   • If at least one participant is not ready, the coordinator sends a rollback command, and all participants revert the changes.

This guarantees that all participants either commit or abort the transaction, ensuring data consistency.