Text fields are not optimised for operations that require per-document field data like aggregations and sorting

[csweJ]

"type" : "illegal_argument_exception",
"reason" : "Text fields are not optimised for operations that require per-document field data like aggregations and sorting, so these operations are disabled by default. Please use a keyword field instead. Alternatively, set fielddata=true on [ent_nm.sort] in order to load field data by uninverting the inverted index. Note that this can use significant memory."