If log rotation is disabled, the log files will continue growing indefinitely. Note also that when rotation is enabled, you can send

SIGHUP

to the process to have it rotate immediately.

above I mentioned log naming… I think altough log rotation is enabled, first the log file name is osquery_result, when it reached 500MB (or aged 28 days) the file renamed as osquery_results-2018-02…. and a new file created osquery_results ….