Database connections idle in transaction
Over the last hour, requests to a couple of API endpoints started timing out waiting for a database connection, then spread. PgBouncer in transaction mode reports its server pool fully checked out, but `pg_stat_activity` shows most of those server connections sitting in `idle in transaction`, some for many minutes, all from one service deployed at the start of the hour. DB CPU is low. The deploy added a new code path that calls an external HTTP API in the middle of a DB transaction. Triage and mitigate.
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.