Es reports an error when executing aggregate query: alternately, set fielddata = true on

GET /megacorp/employee/_search
{
  "aggs": {
    "all_interests": {
      "terms": { "field": "interests" }
    }
  }
}

Execute the following command to start fielddata

PUT /your_index_name/_mapping?pretty
{
  "properties": {
    "your_field_name": { 
      "type": "text",
      "fielddata": true
    }
  }
}