Dirty Read
A dirty read is a transaction reading another transaction uncommitted modification; if that transaction rolls back, the reader saw data that never existed.
Purpose
To understand the risk of the lowest isolation level and ensure critical transactions never read uncommitted data.
Mechanism
Transaction A modifies row X without committing; transaction B reads the modified X. If A rolls back, B has read dirty data (never committed). Read committed and stronger isolation levels prevent this.
Use cases
- Transaction isolation analysis
- Data consistency audit
- Isolation level selection