Data in MapR-DB is stored as byte arrays. When data is replicated to an index in Elasticsearch, the gateways can convert your source data to Elasticsearch data types in three different ways.
By default, MapR-DB assumes that source data is UTF-8 encoded, and gateways convert the source data to strings. If you use this default conversion, you do not have to create destination indexes with the Elasticsearch API before loading them and replicating to them. However, your applications might require your data to be in other data types.
Instead of this default conversion, you can use two different methods of converting data to Elasticsearch data types.