After migrating database from local to a remote mariadb located on a synology nas, I’ve (mass) encountered this error :
Error in database connectivity: (_mysql_exceptions.OperationalError) (1205, 'Lock wait timeout exceeded; try restarting transaction')
This answer helped me very well : https://stackoverflow.com/a/15252722/6166130
I have no more logs regarding this error in home-assistant.log. But I don’t know if this is the right way.
Hope it helps.