Changing Solr types 

Changing a Solr type mapper is rarely if ever done and is not recommended; however, for particular circumstances, such as converting the Solr LongField to TrieLongField, configure the dseTypeMappingVersion using the force option.

The Solr type mapping version defines how Solr types are mapped to Cassandra Thrift or Cassandra types. Changing a Solr type mapper is rarely if ever done and is not recommended; however, for particular circumstances, such as converting Solr types such as the Solr LongField to TrieLongField, you configure the dseTypeMappingVersion using the force option.

The Cassandra internal validation classes of the types you are converting to and from must be compatible. Also, the actual types you are converting to and from must be valid types. For example, converting a legacy Trie type to a new Trie type is invalid because corresponding Cassandra validators are incompatible. The output of the CLI command, DESCRIBE keyspace_name, shows the validation classes assigned to columns.

For example, the org.apache.cassandra.db.marshal.LongType column validation class is mapped to solr.LongType. You can force this column to be of the TrieLongField type by using force="true" in the solrconfig.xml, and then performing a Solr core reload with reindexing.
<dseTypeMappingVersion force = "true">1</dseTypeMappingVersion>

Use this option only if you are an expert and have confirmed that the Cassandra internal validation classes of the types involved in the conversion are compatible.

To use DSE Search data from a 3.0 release or earlier, use the legacy type mapping.