Controlling Athena Query Output Filenames in S3

When working with Amazon Athena and Python, a common requirement is to save query results to Amazon S3. While Athena provides the OutputLocation parameter to specify where results are stored, there’s an important nuance: you can specify the folder (prefix) in S3, but not the exact filename.

---

How Athena Handles Output Files

When you run a query in Athena:

• The OutputLocation is the S3 folder where the results will be stored.
• Athena automatically generates a filename based on the query execution ID, such as:
• <query-execution-id>.csv
• This filename cannot be directly controlled through the Athena API.

So even if you set OutputLocation=’s3://my-bucket/athena-results/’, Athena will still generate something like s3://my-bucket/athena-results/<query-execution-id>.csv.

---

Workaround: Renaming the File After Query Execution

To control the filename, you can copy or move the generated file after the query completes. Here’s a Python example using boto3:

---

Key Takeaways

1. OutputLocation specifies a folder, not a filename. Athena always generates a CSV named after the query execution ID.
2. To use a custom filename, copy or move the file after the query finishes.
3. Using this method, you can organize your Athena query results in S3 with predictable filenames for downstream processing or automation.

This approach provides a simple and reliable way to control filenames for Athena query results without needing to rely on Athena to handle naming.