Idle transaction locks after deploy
It's 09:14 and your payments API p99 latency jumped from 80ms to 6s, with a rising trickle of 500s. The app tier dashboards show CPU at 30% and memory flat — nothing looks saturated there. The Postgres dashboard shows active connections pinned at the 200 max for the primary, a deep `ClientRead`/`Lock` wait spike, and `pg_stat_activity` full of sessions in `idle in transaction`. A deploy went out at 09:05 that added a new 'order summary' endpoint. Walk me through how you triage this and what you do in the next 10 minutes versus the next week.
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 30 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.