Glue Crawler mixes schemas when CSV layouts share a folder
AWS Glue
- Habib Abdurrasyid
- 27 Sep, 2026
- · 1 min read
What happened
I pointed a Glue Crawler at an S3 folder holding two CSV layouts. It registered one table with a mix of both column sets.
What I learned
The Crawler treats one folder as one table. Files with different structures must live in different folders, otherwise the Data Catalog inherits the mess.
The rule I keep
One folder, one schema, one layout. Tidy on the way in, or expensive on the way out.