Last spring our search box was slow. A query took two seconds on a good day, and people noticed.

We started by measuring. Most of the time went to one join that ran on every request, so we moved that work to the moment a post is saved.

Then we looked at the ranking code. It sorted every match, even when we only showed ten. Now it keeps the best ten as it goes.

The result: a search takes about forty milliseconds, and the code is smaller than before.