1. A method for searching data, the method comprising: providing a field searchable data store comprising a plurality of event records, each event record comprising a time-stamped portion of raw machine data; receiving a collection query that references a field name; responsive to the collection query, generating an inverted index by: determining an extraction rule associated with the field name; extracting a field value corresponding to the field name from one or more event records in the field searchable data store using the extraction rule; and populating the inverted index responsive to each extracted field value, wherein each entry comprises the field name, the corresponding field value and a reference value that identifies a location in the field searchable data store where an associated event record is stored.