Crippling database performace

Help! mysql is running like a dog every time RT performs this query:

SELECT DISTINCT main.* FROM Tickets main, Watchers Watchers_1 LEFT JOIN
Users as Users_2 ON Watch

When would RT do this? How can I make this faster?

Mysql shows:

State: Copying to tmp table

I really don’t understand enough about RT or mysql to fix this by

Teo de Hesselle, It’s nice to be loved,
Unix Systems Administrator, but there’s a lot to be
University of Technology, Sydney. said for terrified respect