Container_type - Mysql. How to...

[alexsyi]

If container_type parameter - 'File' chat works well. But if it's 'Mysql' there is one problem.
The problem - when closing window with chat and coming again there are no messages shown although params['max_msg']=25 and params['quit_on_closedwindow']=false! How to change this?
And another question:
How to clear table in mysql. In some time it will be very big so It is usefull to have command to clear it.