Amazon Athena Query Result Reuse for Cost Optimization
Short answer
B Use the query result reuse feature of Amazon Athena for the SQL queries to avoid scanning data twice for identical queries.
Question
Key Takeaways
The question tests knowledge of Athena's native cost-saving features versus data engineering optimizations, with the common trap being the selection of Apache Parquet (D) due to its general performance benefits rather than addressing the specific 'identical query' scenario.
This page explains how to optimize Amazon Athena costs using the built-in query result reuse feature, which caches results from identical queries executed within a short timeframe. It establishes that this solution meets cost and operational overhead requirements better than format conversion or infrastructure changes.
Common mistake: Many candidates choose Option D (Apache Parquet) because it significantly reduces scan size and improves query speed generally. However, this requires an additional ETL step (Glue job change), increasing operational overhead and failing the 'least operational overhead' constraint compared to the zero-config reuse feature.
Expert Analysis
Why the Answer Is Correct
Option B is correct because Amazon Athena’s Query Result Reuse feature automatically caches the results of SQL queries executed within the last 24 hours. When an identical query is run again, Athena returns the cached result instead of scanning the underlying S3 data, effectively reducing the cost to $0 for repeated scans. This aligns perfectly with the requirement for a standard data refresh frequency where the same BI queries are likely executed hourly against the same daily dataset. It requires no additional infrastructure setup.
Why the Other Options Are Wrong
Option A is incorrect because moving data to Glacier Deep Archive introduces retrieval latency and costs, which does not directly reduce Athena query costs for active data and adds complexity. Option C is incorrect because adding ElastiCache introduces significant operational overhead and ongoing costs, violating the 'no additional infrastructure costs' constraint. Option D is incorrect while beneficial for performance, converting data to Parquet requires modifying the Glue job logic, which increases operational overhead compared to simply enabling a feature flag like query reuse.
Community Comment Notes
The community heavily favored Option B, with users noting that query reuse is designed specifically for scenarios where identical queries are re-run. One commenter highlighted that Parquet helps all queries but doesn't address the 'least overhead' constraint as well as reuse. Another user pointed out that since the Glue job updates once a day, the data remains static for that day, making repeated queries ideal candidates for caching.
Official Reference
https://docs.aws.amazon.com/athena/latest/ug/query-result-reuse.html
This link opens the official vendor documentation in a new tab.
Exam Strategy
When asked for 'least operational overhead,' prioritize AWS managed features that require configuration changes over architectural changes like format conversions or new service deployments. Always check if the scenario involves repeated identical operations, which often signals cache or reuse features.
Frequently Asked Questions
Why isn't changing to Parquet the best answer?
Does Query Result Reuse work for different queries?
Community Votes
100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 7 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 7
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rralucard_ 👍 6 Answered Bhttps://docs.aws.amazon.com/athena/latest/ug/performance-tuning.html Use the Query Result Reuse Feature of Amazon Athena. This leverages Athena's built-in feature to reduce redundant data scans and thus lowers query costs.
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Ousseyni 👍 2 Answered BB. Use the query result reuse feature of Amazon Athena for the SQL queries.
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rsmf 👍 1 Answered BWhy not D? The question specifies the option with the least overhead, and it clearly states that the Glue job runs once a day. Since the data for that day will not change, there’s no need for additional overhead.
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Ell89 👍 1 Answered DD query result reuse will benefit the same queries that are being re-run, it wont benefit new queries. parquet will benefit all queries.
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MinTheRanger 👍 1D. Because "query reuse feature" is reliable only when it's identical but here hourly refresh might be on data related to that hour.
Show 2 more comments
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FuriouZ 👍 1 Answered BIt's B: Glacier adds more retrieval time and the other options cost some money
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MinTheRanger 👍 3Why not D?
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