Your question is Query Optimization and Pipeline Flow. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Describe a time you improved a data pipeline by optimizing queries; walk me through your project flow and the query optimization techniques you used.
Explain how you identified the bottleneck, established a performance baseline, changed the pipeline or data model, and validated the result. Include the technologies involved, how you protected data correctness, and how you monitored the optimization after release.