Embodiments of the present disclosure provide a method for generating an inverted index in accordance with a user generated collection query. The method comprises providing a field searchable data store that comprises a plurality of event records, each event record comprising a time-stamped portion of raw machine data. The method further comprises receiving a collection query that references a field name. Further, responsive to the collection query, an inverted index is generated by: a) determining an extraction rule associated with the field name; b) 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 c) 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.