Hi, Currently this is expected because the FileSink is built to support running with higher parallelism. Therefore it needs to periodically write files. The respective file names always have a descriptor that the File Sink knows which files have already been written. You can read more about the FileSink here [1].
Best, Fabian [1] https://ci.apache.org/projects/flink/flink-docs-master/docs/connectors/datastream/file_sink/
