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DAS-C01 · Question #58

A company wants to optimize the cost of its data and analytics platform. The company is ingesting a number of .csv and JSON files in Amazon S3 from various data sources. Incoming data is expected to…

The correct answer is A. Use an AWS Glue ETL job to compress, partition, and convert the data into a columnar data. Amazon Athena charges based on the amount of data scanned per query. To minimize cost and meet the <1 minute query SLA, the optimal strategy is to (1) convert raw CSV/JSON to a columnar format (like Parquet or ORC) using AWS Glue ETL - columnar formats allow Athena to skip…

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Question

A company wants to optimize the cost of its data and analytics platform. The company is ingesting a number of .csv and JSON files in Amazon S3 from various data sources. Incoming data is expected to be 50 GB each day. The company is using Amazon Athena to query the raw data in Amazon S3 directly. Most queries aggregate data from the past 12 months, and data that is older than 5 years is infrequently queried. The typical query scans about 500 MB of data and is expected to return results in less than 1 minute. The raw data must be retained indefinitely for compliance requirements. Which solution meets the company's requirements?

Options

  • AUse an AWS Glue ETL job to compress, partition, and convert the data into a columnar data
  • BUse an AWS Glue ETL job to partition and convert the data into a row-based data format. Use
  • CUse an AWS Glue ETL job to compress, partition, and convert the data into a columnar data
  • DUse an AWS Glue ETL job to partition and convert the data into a row-based data format. Use

How the community answered

(30 responses)
  • A
    47% (14)
  • B
    13% (4)
  • C
    7% (2)
  • D
    33% (10)

Explanation

Amazon Athena charges based on the amount of data scanned per query. To minimize cost and meet the <1 minute query SLA, the optimal strategy is to (1) convert raw CSV/JSON to a columnar format (like Parquet or ORC) using AWS Glue ETL - columnar formats allow Athena to skip irrelevant columns and compress data far more efficiently than row-based formats; (2) partition the data (e.g., by date) so Athena only scans the relevant partition rather than the entire dataset; and (3) apply S3 Lifecycle policies to transition data older than 5 years to a cheaper storage class (e.g., S3 Glacier) since it is infrequently queried, while still retaining it indefinitely for compliance. Options B and D are wrong because row-based formats (like CSV or Avro) do not support column pruning - Athena must scan entire rows, increasing cost and latency. Option C likely omits the lifecycle policy for aging data, making it more expensive for rarely accessed cold data.

Topics

#AWS Glue ETL#Athena performance optimization#Data partitioning#Columnar data formats

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