DEA-C01 Question 281
Single answerYour team is using Amazon Athena to query data stored in an S3 data lake. The data schema in the data lake has recently changed to include new columns, but the old columns remain unchanged. You want to ensure that your queries in Athena continue to work without requiring modifications to the existing table definition. Which schema evolution technique should you use?
- A
Use the 'ALTER TABLE ADD COLUMNS' command to update the table schema in Athena.
- B
Enable the 'Partition Projection' feature in Athena.
- C
Manually update the schema in the AWS Glue Data Catalog using the Amazon Glue Console.
- D
Allow Athena to infer the schema automatically from the data during each query execution.
Show answer and explanation
Correct answer: A
Explanation
When using Amazon Athena to query data with schema changes, the 'ALTER TABLE ADD COLUMNS' command is the recommended approach for handling schema evolution involving new columns. This ensures that the table definition in Athena remains compatible with the updated data schema while avoiding the need to recreate the table or modify existing columns.
- A. Correct.
This is the correct answer. The 'ALTER TABLE ADD COLUMNS' command allows you to add new columns to the table schema in Athena without modifying existing columns, ensuring schema evolution compatibility.
- B. Incorrect.
Partition Projection is a feature for optimizing query performance by predefining partition metadata. It does not handle schema evolution for new columns in the data.
- C. Incorrect.
Manually updating the schema in AWS Glue Data Catalog is a valid option, but it is not the most efficient or recommended method for schema evolution in this scenario.
- D. Incorrect.
Athena does not automatically infer schema changes during each query execution. You need to explicitly update the schema to reflect any changes in the underlying data.