(PECL solr >= 0.9.2) Checks if the property exists

(PECL solr >= 2.2.0) Sets the field to collapse on

(PECL sphinx >= 0.1.0) Set matches sorting mode

(PECL solr >= 2.2.0) Returns the group.sort value

(PECL solr >= 0.9.2) Removes one of the stats.facet parameters

(PECL solr >= 2.2.0) Returns an array of fields

(PECL solr >= 0.9.2) Destructor public void

(PECL solr >= 0.9.2) Rollbacks all add/deletes made to the index since the last commit

(PECL solr >= 2.2.0) Returns the group.limit value

(PECL solr >= 0.9.2) Sets the minimum document frequency used for determining term count