Search omitting some results

Silverstripe Version:
4.1
MySQL version 5.5.6
Question:

I’ve implemented a Site Search successfully, but it appears to be omitting some results randomly. They generally appear to be searches that aren’t English words, specifically brand names. These names are clients such as ASB or ANZ, so it’s quite important that they show up.

I’ve tried manually searching in the database with a “LIKE” query and it works.

Where can I find the query that the search uses, so I can modify it?

I can now answer my own question, for future reference.
Turns out it’s nothing to do with SilverStripe at all. There is a default minimum word length set in MySql for a Fulltext Search of 4 characters, which is why it wasn’t finding any 3-letter acronyms. What makes it confusing is that it will return results if the 3 letters are a partial match to an indexed word.
To change this you need to edit the my.cnf file (or my.ini on Windows) and add the following line under the [mysqld] section:

ft_min_word_len=3

and then 3-letter words will be indexed