getting multiple parquet file instead of single file in DMS service

I'm trying to migrate the RDS data in to S3 using AWS DMS service. In S3 target endpoint i specify "DataFormat": "parquet". when I run the migration task for large amount of database table I found multiple parquet files got generated, but i was expecting single file.

Is there any configuration to make a single parquet data file? Also if its by default configuration then what is default size for splitting into multiple files.