The error is from mi_mark_crashed(file) in ha_myisam::check, when it calls _mi_report_crashed, and the thread which has table open is unknown. But to know more, you will need to provide more context to this error message from error log.
The error is from mi_mark_ crashed( file) in ha_myisam::check, when it calls _mi_report_crashed, and the thread which has table open is unknown. But to know more, you will need to provide more context to this error message from error log.