Good search term in Sphinx

Question

Using Rails 3.2, Sphinx Search and Thinking Sphinx gem. I have tried wrapping % and *, and wildcard, in the keywords in my controller, but can't achieve what I want:

Keywords to search:

• world trade
• worldtrade
• worl trade
• trade world
• trad worl

Expected matched search results:

• World Trade Center

How should I format the keywords in my controller so that I get the expected search result with the different keywords as shown above?

Answer 1

• For Sphinx, the wildcard character is * - so there's no point using %.
• If you want every query to have wildcards added to it, use :star => true in your Thinking Sphinx search call.
• If you want to match on parts of words, you need to enable either min_prefix_len or min_infix_len. The default is 0 (disabled), but given your examples, perhaps 4 is a good setting? The lower it is, the larger your index files get (and so searches may get slower as well), so perhaps don't set it to 1 unless you need to.
• All of the above points won't make 'worldtrade' match, because you're providing one long word instead of two separate ones. You could look into adding a wordforms file to your Sphinx configuration, but that may be overkill in this case, as you'd want to cover each specific case.