Here are some basic, but high impact ways to optimize MySQL for Drupal (there are much more sophisticated and expensive ways to speed up your database of course):
Am not sure if these tips do any good for someone on a shared hosting plan or not (do shared plans have access to a my.cnf file?). Also, I can only confirm these setting for MySQL 4.0.2 thru the latest 4.0.x version, but I think it would work for 5.x (maybe someone can confirm this and leave a comment...).
Actually, it will work for below 4.0.2 I think as long as you add
set-variable = before each line (see this page for more on set-variable)
1. Get this script, upload it, unzip it, and install it in your /etc folder (at the root of your server, not your Drupal install, right). Then run it from the command line by entering
The script will run and what you'll be left with is an output with some info and suggestions about your MySQL settings. Was shocked to learned that on my VPS the cache was not even enabled - very helpful to know!
2. Next open your my.conf file in pico or some kind of proper code/text editor: