My local phpMyAdmin (or more probably the underlying MySQL) keeps timing out after half an hour, and I have to log in again. This may be a good secrity feature in a production environment, but its very irritating during development, How can I reset it, please ?

Conversely my production phpMyAdmin (at my web host) doesn't seem to time out at all, and has no 'Log Out' button on the dashboard. Should I be able to log out ? I want to log out, not close the MySQL server, of course.