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Performance Engineering and Cost Optimization Questions

Engineering practices and trade offs for meeting performance objectives while controlling operational cost. Topics include setting latency and throughput targets and latency budgets; benchmarking profiling and tuning across application database and infrastructure layers; memory compute serialization and batching optimizations; asynchronous processing and workload shaping; capacity estimation and right sizing for compute and storage to reduce cost; understanding cost drivers in cloud environments including network egress and storage tiering; trade offs between real time and batch processing; and monitoring to detect and prevent performance regressions. Candidates should describe measurement driven approaches to optimization and be able to justify trade offs between cost complexity and user experience.

EasyTechnical
59 practiced
Explain how compression codecs and column encodings reduce storage and IO for analytics. Given numeric (transaction_amount) and high-cardinality string (user_id_hash) columns, recommend encoding/compression techniques and explain why.
HardSystem Design
61 practiced
Describe workload shaping techniques (throttling, query queuing, resource groups) to protect dashboard workloads from noisy analysts running expensive ad-hoc queries. Propose a practical implementation plan for either Redshift or Snowflake and describe trade-offs.
HardTechnical
46 practiced
You must reduce the average runtime of a heavy nightly report from 60 minutes to under 15 minutes. Propose a tactical optimization plan (query tuning, pre-aggregation, parallelization, caching) with an order of operations and quick-win items that provide measurable benefits within the first week.
MediumTechnical
50 practiced
Design a synthetic load-testing plan to evaluate dashboard concurrency and responsiveness for 500 simultaneous users interacting with filters and exporting CSVs. Include test data generation, user-behavior modeling, metrics to capture, and pass/fail criteria for the test.
HardTechnical
47 practiced
Design a storage tiering policy (hot/warm/cold) for historical analytics data spanning 10 years to balance cost and query latency. Provide rules for data movement (age thresholds, access frequency), expected cost savings, and the impact on ad-hoc analyst queries.

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