Summary (cont.)
Basic approach: Two Phase Commit:
- works.
- pays in forced disk writes.
- vulnerable to coordinator failure at certain times.
Three Phase Commit:
- pays even more in forced disk writes.
- most of the time solves the vunlerability problem of 2PC when quorum exists.
Enhanced Three Phase Commit:
- Costs exactly as 3PC, but with better logic.
- Always solves the vulnerability problem of 2PC when quorum exists.