Troubleshooting Amazon Athena Queries for Partitioned S3 Data

DEA-C01 By islever Editorial Last updated

Automate data processing by using AWS services. Manage the lifecycle of data.

Short answer

AC Confirm the S3 location and use MSCK REPAIR TABLE to sync partition metadata.

Question

A company has a data lake in Amazon S3. The company collects AWS CloudTrail logs for multiple applications. The company stores the logs in the data lake, catalogs the logs in AWS Glue, and partitions the logs based on the year. The company uses Amazon Athena to analyze the logs. Recently, customers reported that a query on one of the Athena tables did not return any data. A data engineer must resolve the issue. Which combination of troubleshooting steps should the data engineer take? (Choose two.)
  1. Confirm that Athena is pointing to the correct Amazon S3 location. Correct Answer
  2. Increase the query timeout duration.
  3. Use the MSCK REPAIR TABLE command. Correct Answer
  4. Restart Athena.
  5. Delete and recreate the problematic Athena table.

Key Takeaways

Tests troubleshooting partitioned data lakes where missing metadata or wrong paths cause zero results, a common trap confusing infrastructure checks with schema repairs.

This page explains how to troubleshoot empty query results in Amazon Athena by verifying S3 paths and repairing table metadata partitions.

Common mistake: Users often choose B (timeout) or D (restart), failing to realize that empty results indicate missing data or metadata, not performance issues.

Expert Analysis

Why the Answer Is Correct

The correct options are A and C. When an Athena query returns no data despite logs being present, the two most likely causes are incorrect source paths or stale partition metadata. Option A is critical because if the table definition points to the wrong S3 prefix, Athena sees no files. Option C addresses the specific scenario of partitioned data; when new partitions are added to S3 without updating the Glue catalog, the MSCK REPAIR TABLE command synchronizes the metastore with the actual S3 directory structure.

Why the Other Options Are Wrong

Option B is incorrect because increasing timeout does not retrieve non-existent data. Option D is invalid as Athena is a serverless service that cannot be restarted by users. Option E is dangerous and unnecessary; dropping and recreating the table risks losing configuration and does not fix underlying path or partition sync issues.

Community Comment Notes

Community consensus strongly supports AC. As kupo777 noted, confirming the S3 location is a 'critical first step' before attempting metadata repairs. While one user suggested B, others correctly pointed out that timeout issues result in errors, not empty results, making AC the only logical combination for this symptom.

Exam Strategy

When troubleshooting Athena, always distinguish between 'no data found' (path/metadata issue) and 'query failed' (permission/timeout issue). For partitioned tables, always consider MSCK REPAIR TABLE if data was recently added.

Frequently Asked Questions

Why not just delete and recreate the table?

Recreating loses configurations and doesn't fix the root cause if the path is wrong or partitions are desynced.

Does MSCK REPAIR TABLE work for all table types?

It primarily works for Hive-style partitioned tables stored in S3. It may not work for external tables with complex formats like Parquet without proper SerDe settings.

More DEA-C01 FAQ →

Community Votes

AC
100%

100% of anonymous learners picked answer AC. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 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 3

  1. kupo777 👍 3
    Correct Answer: AC A. Confirm that Athena is pointing to the correct Amazon S3 location. This is a critical first step to ensure that the data source Athena is querying matches the actual location of the CloudTrail logs in S3. If the path is incorrect, Athena will not find the data. C. Use the MSCK REPAIR TABLE command. If the data lake is partitioned, using the MSCK REPAIR TABLE command can help update the table metadata in Athena. This command will add any missing partitions to the table, which may resolve issues related to missing data if new partitions were added but not reflected in Athena.
  2. michele_scar 👍 2
    B and D definitely wrong E should be dangerous
  3. truongnguyen86 👍 1
    should be A, B. D and E are incorrect, C: MSCK REPAIR TABLE is a Hive command in Amazon Athena not for S3

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