elasticsearch/elasticsearch-net — pull request #644 by danp60 (2014-05-07 00:53:29+00:00)
Title: Support doc_values attributes on numeric and string mappings and in ElasticProperty attributes

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-core-types.html

Doc values are a new feature introduced in 1.0 to store field data in a column stride fashion. This allows for fast access to field data via fs cache without needing to put the field in the jvm heap.