Only column headers appearing in Athena

This issue where only column headers appear in Athena after using a Glue crawler to process CSV files from S3 is a common problem that can occur for several reasons:

1. Crawler configuration: The crawler may be set to only extract headers from the CSV file without processing the actual data. Double-check your crawler settings to ensure it's configured to extract both headers and data.

2. File format issues: Ensure that your CSV files are in a format supported by AWS Glue. Sometimes, inconsistencies in delimiters, quote characters, or file encoding can cause problems.

3. Permissions: Verify that the IAM role assigned to the Glue crawler has the necessary permissions to access and read the data in your S3 bucket.

4. Data location: Make sure the S3 path specified in the crawler configuration matches the actual location of your data files.

5. Multiple runs: In some cases, running the Glue crawler multiple times may be necessary to fully populate the Glue Data Catalog.

6. File structure: If your CSV files have a complex structure or nested data, the crawler might have difficulty interpreting it correctly.

To resolve this issue:

1. Review and adjust your crawler configuration if necessary.
2. Check the format and structure of your CSV files.
3. Verify IAM permissions for the Glue crawler.
4. Ensure the correct S3 path is specified in the crawler settings.
5. Try running the crawler multiple times.
6. Review the Glue crawler logs for any error messages or warnings that might provide additional insights.

If the problem persists, you may need to consider using alternative methods, such as creating a custom classifier or manually defining the table schema in the Glue Data Catalog.
Sources
AWS Glue Crawler not extracting data from CSV file | AWS re:Post
crawler never load data | AWS re:Post

Hello.

Can you view crawled CSV data on the Glue console?
Also, would it be possible for you to share the CSV sample you are using?