If you find that searching gets to be a performance bottleneck, one thing you can do is to build custom indices for the pages in the database. You can build an index for each word in the text, and another with word pairs in the text. (This, for example, would have an entry "if you", "you find", "find that" and so on) Searching for phrases is just a matter of splitting the phrase into pairs and searching for documents that match all the pairs. (It's generally good enough)

You might not have to do this--there's only 180K pages here, so full-text searches may very well not be performance bottlenecks at the moment.