fq vs. q

[Martin Davidsson]

I've tried to read up on how to decide, when writing a query, what  
criteria goes in the q parameter and what goes in the fq parameter, to  
achieve optimal performance. Is there some documentation that  
describes how each field is treated internally, or even better, some  
kind of rule of thumb to help me decide how to split things up when  
querying against one or more fields. In most cases, I'm looking for  
exact matches but sometimes an occasional wildcard query shows up too.  
Thank you!

-- Martin