10 - 2PC

#cs454

Reading: 8.5

1. Coordinator gets participants ready to commit their writes
2. Everybody commits

Rules

• Coordinator aborts a transaction iff at least one participants votes to abort it.
• Coordinator commits a transaction iff all participants vote to commit it.

2PC State §

• L1: logs transaction id, list of participants, transaction metadata
• L2: logs request and vote
• L3: logs decision
• L4: commit to disk
• L5: cleanup

2PC Failures §

1. Abort
2. Abort
3. Abort
4. Check vote in log
5. Timeout retry
6. Check log
7. Block