Three Transactions, Three Variables
End-to-End Coordination
An end-to-end trace of three concurrent transactions interacting with the logging and locking systems.
The Setup: T1, T2, T3 Operating on A, B, C
Three transactions run concurrently, each targeting a different variable. The Transaction Manager's job? Keep these operations from stepping on each other's toes.
Scenario 1: All Transactions Commit
✅ Commit Path Coordination
Lock acquisition: Each transaction employs Strict Two-Phase Locking (S2PL), unlocking only at COMMIT or ABORT. The same microschedule applies to 2PL.
WAL entries: Changes are logged in sequence as they happen.
Final state: Post-COMMIT, all changes are locked in and durable.
Scenario 2: Mixed Outcomes - T2 Aborts
❌ Abort Handling
WAL UNDO: Revert T3's changes using old values.
What's Next?
The Transaction Manager ensures these components handle concurrent transactions without a hitch.
Up next: Watch how these elements synchronize across the entire transaction lifecycle!