Interview Pro Tip
Pro-Move: 'Spark UI showed 1 partition at 4hr—salted the key, added pruning; 6hr to 90min; documented in runbook.' Red Flag: We added more resources—optimization, not scaling.
**STAR**: **Situation**: Nightly job took 6 hr; SLA 2 hr. **Task**: Optimize. **Action**: Profiled—found full scan and skew. Partition pruning; broadcast join for dimension; salting for skew. **Result**: 1.5 hr; 4x improvement....
The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations. It covers performance optimization strategies, common pitfalls to avoid, and real-world examples from companies like Swiggy. The answer also includes follow-up discussion points that interviewers commonly explore.
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