how schedul work with optional and mandatory prompts

Hi,

i wante to understand  this  case :

i have a webi with mandatory prompt "year" and optional prompt "city", i scheduled this document with prompt value of year=2014 ( no value for city)

normally when a user  enter a year 2014 like prompt he view the instance of document  ?

but ifhe put the value2014 andParisas a city,webiwillquery the database(whichis slow)orit filterthe instance ?

i  want to understand how schedul work when i have optional and mandatory prompts in the same webi document

Thanks