Databases & Storage · core
Transaction Processing
ACID, MVCC, isolation anomalies, locking, optimistic control, serializability, commit, and recovery.
Mental model
A transaction provides an illusion over concurrency and failure. Isolation defines which histories are legal; logging and commit protocols decide what survives.
How to study Transaction Processing
Begin by restating the mental model in your own words, then connect it to a concrete system you have built or operated. Name the mechanism, the constraint it addresses, and the trade-off it introduces. Use PostgreSQL Transaction Isolation to check details, but close the source before writing your explanation. Retrieval is the learning step; rereading is only preparation.
Next, compare Transaction Processing with the neighboring concepts in its roadmap. Ask what changes in correctness, latency, resource use, operability, and failure recovery. Complete Design exercise: Transaction Processing and preserve the command, input, output, and one failed attempt as evidence. Finish by explaining the idea without jargon to someone who has not studied the track.
Proof of understanding
- Explain the mechanism from first principles and identify the state it reads or changes.
- Give one situation where the concept is the right choice and one where it is not.
- Predict a realistic failure mode before running the drill, then compare the prediction with evidence.
- Connect the result to a roadmap or build artifact instead of treating the concept as isolated trivia.
Learn from primary sources
Practice and explain it back
Design exercise: Transaction Processing
ACID, MVCC, isolation anomalies, locking, optimistic control, serializability, commit, and recovery. Implement designOutline() returning non-empty values for: isolationLevel, concurrencyControl, commitRecovery. Each value must name a concrete mechanism or decision.
Expected evidence: A design outline with isolationLevel, concurrencyControl, commitRecovery plus an explicit failure mode or trade-off.
Open the interactive drill →Review prompts
- Snapshot isolation prevents dirty and non-repeatable reads but is not serializable. What anomaly survives, and what fixes it?
Build evidence
Toy write-ahead log
An append-only WAL with crash recovery.
- Append + fsync before acknowledging a write
- Replay the log to recover state after a crash
- Checkpoint/truncation to bound log size
Prerequisites
None assigned yet.
Related concepts
None assigned yet.