WARNING: Version 2.0 of Elasticsearch has passed its EOL date.
This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.
unique token filter can be used to only index unique tokens during
analysis. By default it is applied on all the token stream. If
only_on_same_position is set to
true, it will only remove duplicate
tokens on the same position.