Reporting queries timeout
The reporting service intermittently throws `TimeoutException: could not acquire a connection from the pool within 30000ms`. It correlates with mornings when analysts run dashboards. The HikariCP pool size is 20. Dashboards: `pool.active` sits at 20 during incidents while `pool.pending` (waiters) spikes; the database itself reports only ~30% of its `max_connections` used and is healthy. A change last week added an export endpoint that streams a large result set to the client while holding the DB connection open for the whole download. Triage and fix.
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 35 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.