title: iOS Core Data Indexed Attribute not improving performance
body: <p>I have a Core Data database running on an iPad.  It has 30,000 contacts in it with attributes such as firstname, lastname etc.</p>
  
  <p>The search performance isn't great using an NSCompoundPredicate.  I am or'ing two LIKE Predicates (on firstname and lastname) and it is taking around 1500ms to search the 30,000 contacts.  I then tried adding the 'indexed' property to the firstname and lastname fields (using the XCode Data Modeller UI) but the performance seems exactly the same.</p>
  
  <p>Since adding the Indexed property to the two fields I have removed all objects from the database and re-populated it.  Do I need to do anything more in order for the indexes to start to be used, and should I expect to see a performance improvement by indexing the two fields being used within the compound predicate?</p>
  
  <p>I am running on a real device (an iPad3).  1500ms to search through 30,000 contact records doesn't seem that great - is it par for the course?</p>
  
  <p>Many thanks.</p>