Apache Solr Reference Guide Covering Apache Solr 6.0

done in schema.xml.
Enabling a field for docValues only requires adding docValues="true" to the field (or field type) definition, as
in this example from the schema.xml of Solr's sample_techproducts_configs config set:
If you have already indexed data into your Solr index, you will need to completely re-index your content
after changing your field definitions in schema.xml in order to successfully use docValues.
DocValues are only available for specific field types. The types chosen determine the underlying Lucene
docValue type that will be used. The available Solr field types are:
1.
2.
StrField and UUIDField.
If the field is single-valued (i.e., multi-valued is false), Lucene will use the SORTED type.
If the field is multi-valued, Lucene will use the SORTED_SET type.
Any Trie* numeric fields and EnumField.
If the field is single-valued (i.e., multi-valued is false), Lucene will use the NUMERIC type.
If the field is multi-valued, Lucene will use the SORTED_SET type.
These Lucene types are related to how the values are sorted and stored.
There are two implications of multi-valued DocValues being stored as SORTED_SET types that should be kept
in mind when combined with /export (and, by extension Streaming Aggregation-based funcitonality):
Values are returned in sorted order rather than the original input order.
If multiple, identical entries are in the field in a single document, only one will be returned for that
document.
There is an additional configuration option available, which is to modify the docValuesFormat used by the field
type. The default implementation employs a mixture of loading some things into memory and keeping some on
disk. In some cases, however, you may choose to specify an alternative DocValuesFormat implementation. For
example, you could choose to keep everything in memory by specifying docValuesFormat="Memory" on a
field type:
Please note that the docValuesFormat option may change in future releases.
Lucene index back-compatibility is only supported for the default codec. If you choose to customize the d
ocValuesFormat in your schema.xml, upgrading to a future version of Solr may require you to either
switch back to the default codec and optimize your index to rewrite it into the default codec before
upgrading, or re-build your entire index from scratch after upgrading.
Using DocValues
Sorting, Faceting & Functions
If docValues="true" for a field, then DocValues will automatically be used any time the field is used for sortin
g, faceting or Function Queries.
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