Interview prep
Answers should be evaluated like an interviewer would evaluate them
This page focuses on question framing and reasoning structure. It should not imply validated model answers until those are written and reviewed properly.
Verification pending
Interview entries are draft prompts and evaluation structure only. They are not yet final answer keys.
seniorMVCCIsolation levelsRetry strategy
Explain REPEATABLE READ vs SERIALIZABLE in PostgreSQL and when you would choose each.
A strong answer explains snapshot behavior, anomaly protection, retry cost, and the operational burden of high-contention workloads.
Reasoning checklist
- • Define what anomalies each level prevents.
- • Explain that SERIALIZABLE still requires retries.
- • Discuss workload tradeoffs instead of claiming one level is always better.
A reviewed model answer will be added here after the interview pack is fully authored.
midMVCCVACUUMStorage bloat
How does VACUUM relate to MVCC, and what happens if it falls behind?
A strong answer connects dead tuples, storage bloat, xid horizon pressure, and degraded read performance.
Reasoning checklist
- • Tie VACUUM directly to reclaiming dead row versions created by MVCC.
- • Mention bloat and wraparound risk, not just disk usage.
- • Discuss operational symptoms such as slower scans and autovacuum backlog.
A reviewed model answer will be added here after the interview pack is fully authored.