Why empty txt objects appear in s3 bucket ? can i control where to save them?

Question

I'm using step function with many lambdas, python and boto3. some lambdas copy objects from one bucket to another, and some run queries in athena and produce parquet files. At the end of the state machine execution, empty txt files appear in the bucket. I didn't find in aws documentation nor boto3 explanation for that. Can I define aws not to save those files / or set the location ?

The empty txt objects

Answer 1

Check Identifying Query Output Files in https://docs.aws.amazon.com/athena/latest/ug/querying.html . These are the results of your DDL queries that you ran using boto3.

You can change the OutputLocation for only DDL queries so that they can be stored in a different bucket/prefix. If you don't want to store these then you can safely delete them immediately after you ran a DDL query by using the query id returned.