cur_user_text and old_user_text are "tinyblob", so MySQL won't
index them.
Hmm, any reason why you didn't make them binary varchar's? But are you sure our MySQL can't index those? The manual says that since version 3.23.2 you can index BLOB's if you are using MyISAM tables and we use those.
I tried your commands; didn't work because of the BLOB thing.
As we will switch to that codebase when we switch servers,
there's probably
no need to fix minor bugs here for the time being.
The query without an index looks really really expensive to me. If this is what makes Wikipedia unusable at the moment, I wouldn't call it a minor bug.
Any hard evidence to cover that theory?
Maybe we could simply turn it off for a short period and see what happens?
That's probably worth a shot; we could live without that function for a while, and there'd be no information loss if we turn it off. Jimbo? Jason?