IntermediateBEHAVIORAL
Describe a time when you identified a recurring production bug or performance issue in an application you maintained. How did you investigate, prioritize, and resolve it, and what changes did you introduce to prevent recurrence?
Software Engineer
General

Sample Answer

At a fintech startup I inherited alerts showing CPU spikes and 5xx rates every weekday morning that impacted ~20k users. I dug into logs and correlated traces to find a batch job that ran synchronously during business hours and caused DB connection pool exhaustion. I prioritized it because it affected revenue-generating flows and recovery time was long. I split the batch into smaller chunks, added circuit breakers, and moved non-critical parts to an off-peak scheduler. I also added real-time dashboards and an automated rollback for the job. Over four weeks we cut peak 5xxs from 3.8% to 0.2%, reduced mean time to recovery from 45m to 7m, and eliminated the recurring spike.

Keywords

Root-cause via logs/traces and correlating alertsPrioritization based on user impact and revenueConcrete remediation (chunking job, circuit breakers, scheduling)Prevention: monitoring, dashboards, automated rollback