Ledger events missing from warehouse
Finance reports that ~0.2% of `ledger-events` are missing from the downstream warehouse — reconciliation finds gaps with no corresponding Kafka record. No consumer lag, no errors in consumer logs, exactly-once is NOT enabled. Dashboards: the `ledger-events` topic has `replication.factor=3` but `min.insync.replicas=1`; broker logs show two unclean leader elections in the last 24h during a rolling broker restart for an OS patch. The producer config is `acks=1`, `retries=0`. The gaps correlate in time with the broker restarts. Triage and explain the loss.
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.