應該怎樣優化資料庫？

應該怎樣優化數據庫
我使用drupal 6.x.，接到空間商電郵：
We have detected that your account executing a slow MySQL queries.

MySQL Query: select t.word as realword, i.word from search_total t left join search_index i on t.word = i.word wh

Slow MySQL queries are not allowed, because you share server resources with thousands of other users and your long MySQL queries are slowering the server and other users are having MySQL performance and connectivity problems. Please optimize your MySQL queries as soon as possible.
Here are some good articles how to optimize MySQL queries: http://www.google.com/search?q=optimize+mysql+queries

Good tips how you can optimize your scripts and make our servers run faster:
- disable visitors monitoring and tracking (each move of your visitor makes database query)
- disable all unused modules
- disable internal stats for your website - use http://www.google.com/analytics/ for example

我只使用了一家流量統計，沒有不使用的模組和鏈結。請問應怎樣來達到空間商要求？