Index corruption after OS upgrade
After your platform team upgraded the host OS on the database fleet (a major distro bump), a few queries start returning wrong results: a `WHERE email = ?` lookup misses rows that you can plainly see exist when you `SELECT` with a sequential scan, and a `UNIQUE` constraint let in what looks like a duplicate. No app or schema change. The tables are fine; only certain text/index lookups misbehave. `amcheck` on one btree index reports inconsistencies. Triage, mitigate, and prevent recurrence.
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 40 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.