AWS Certified Data Analytics – Specialty DAS-C01 – Question121

A financial company uses Amazon Athena to query data from an Amazon S3 data lake. Files are stored in the S3 data lake in Apache ORC format. Data analysts recently introduced nested fields in the data lake ORC files, and noticed that queries are taking longer to run in Athena. A data analysts discovered that more data than what is required is being scanned for the queries.
What is the MOST operationally efficient solution to improve query performance?

A.
Flatten nested data and create separate files for each nested dataset.
B. Use the Athena query engine V2 and push the query filter to the source ORC file.
C. Use Apache Parquet format instead of ORC format.
D. Recreate the data partition strategy and further narrow down the data filter criteria.

Correct Answer: C