Rollback blocked by schema mismatch
v300 of the user service deployed at 11:00 with a migration that renamed the column 'phone' to 'phone_number' and the app now writes to 'phone_number'. At 11:20 you discover v300 has a separate bug corrupting notification preferences and you decide to roll back to v299. But v299's code reads/writes 'phone' which no longer exists, so a naive rollback will 500 on every request. Meanwhile 20 minutes of writes have only landed in 'phone_number'. Walk me through how you safely get back to a healthy state.
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 45 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.