Database Atomicity

What

All actions in txn happen, or none happen. Not to be confused with atomic in Multi Threading (which is more like isolation)

Use undo log
- both in memory and on disk.
Shadow Paging
- The DBMS makes copies of pages modified by the transactions and transactions make changes to those copies. Only when the transaction commits is the page made visible.
- Slower runtime performance
- Better recovery performance, single thread friendly.
Two Phase Lock