Updated for FileLocator Pro 8.0
FileLocator Pro does not automatically index files but version 8 added new functionality for creating an index over a group of files. Once built the indexes typically provide sub-second search results. The indexes aren't automatically updated so you need to update the index regularly if the data within the index is changeable.
More information on indexing can be found here:
FileLocator Pro: Indexing Interface
As an alternative to indexing FileLocator Pro also has a caching feature where the text extracted from documents (e.g. PDF, Word, Excel) can be cached for very fast searching.
Only text information is stored in the cache and the text is compressed to reduce storage space.
More information here: Cache Settings