User database index

Hi,

Reaching 900 users, searching for users became really slow for me, and I ran accross this SQL query in some forum thread around here, which is supposed to create an index, which supposedly should make searching a little faster:

create index user_key on wp_usermeta(user_id, meta_key);

That said I couldn’t figure out how to use it properly. I’m not big on MySQL, but I know my way around phpMyAdmin and PHP sql queries.

That said, couldn’t figure out on what level I should run this in phpmyadmin, and I keep getting messages like:

#1146 – Table ‘crowdcontrol_co_il.wp_usermeta’ doesn’t exist

etc.

Any help would be appreciated. A quick overview of what this index thing does and the implications would also be appreciated.

Thanks!

Adam