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):
Note that if you are on a shared hosting plan then only your host will be able to tune MySQL since you won't have access to the 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 at the top, 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 sh /path-to-file/tuning-primer.sh
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.cnf file in pico or some kind of proper code/text editor:
Depending on the memory resources you have available you'll want to paste in something like these examples (adjust up or down depending on how your system differs, of course):
For a setup with 500mb of RAM your my.cnf file may look like this:
[mysqld]
max_connections = 150
max_user_connections = 150
key_buffer = 36M
myisam_sort_buffer_size = 64M
join_buffer_size = 2M
read_buffer_size = 2M
sort_buffer_size = 3M
table_cache = 1024
thread_cache_size = 286
interactive_timeout = 25
wait_timeout = 1800
connect_timeout = 10
max_allowed_packet = 1M
max_connect_errors = 1000
query_cache_limit = 1M
query_cache_size = 16M
query_cache_type = 1
tmp_table_size = 16M
For a system with 256mb of ram it may look like this:
[mysqld]
max_connections = 75
max_user_connections = 75
key_buffer = 16M
myisam_sort_buffer_size = 32M
join_buffer_size = 1M
read_buffer_size = 1M
sort_buffer_size = 2M
table_cache = 1024
thread_cache_size = 286
interactive_timeout = 25
wait_timeout = 1000
connect_timeout = 10
max_allowed_packet = 1M
max_connect_errors = 1000
query_cache_limit = 1M
query_cache_size = 16M
query_cache_type = 1
tmp_table_size = 16M
Please note that every server configuration is going to differ and simply pasting these in may cause unexpected results.
3. Save your my.cnf file and restart mySQL. This can be done via your control panel or the command line (on some unixes: service mysqld restart otherwise /etc/rc.d/init.d/mysqld restart or /etc/init.d/mysqld restart)
Your new settings are now active and you can run the script from above again and see the difference in your results. After some experimenting I've found that it is useful to look at the script results right after making a change just to see if your modifications were recognized by the system and get the early returns from whether things were improved or not -- but, to get a truly accurate reading from the script you should check back in 24-48 hours after rebooting mysql (this is actually noted at the top of the script itself, but it doesn't really explain why) depending on your site traffic. Also, I've found that the way I've got Drupal set up it is particularly demanding in the tmp_table_size and table_cache areas (e.g., you may want to bu
