title: Failing to store keyword text field length above 32766
body: <p>I had been trying to store a field as type keyword to support case-sensitive text search,</p>
  
  <p>But when I try to store text with length above 32766 characters it is failing to store it, giving the below exception</p>
  
  <pre><code>    Elasticsearch exception [type=illegal_argument_exception, reason=Document contains at least one immense term in field="case_message_message.lowcase" (whose UTF8 encoding is longer than the max length 32766), all of which were skipped.  Please correct the analyzer to not produce such terms.  The prefix of the first immense term is: '[-32, -80, -84, -32, -79, -122, -32, -80, -126, -32, -80, -105, -32, -80, -77, -32, -79, -126, -32, -80, -80, -32, -79, -127, 58, 32, -32, -80, -107, -32]...', original message: bytes can be at most 32766 in length; got 37632]
  </code></pre>
  
  <p>Is there is any way to store this text above 32766,</p>
  
  <p>Elastic search version 6.1.2</p>
  
  <p>Any help is really appreciated.</p>
  
  <p>UPDATE 1:</p>
  
  <p>This is the mapping of my index I had using a custom normalizer and also normalizer</p>
  
  <pre><code>{
     "org-16-database": {
        "mappings": {
           "org-16-table": {
              "properties": {
                 "My field": {
                    "type": "text",
                    "fields": {
                       "keyword": {
                          "type": "keyword"
                       },
                       "lowcase": {
                          "type": "keyword",
                          "normalizer": "my_normalizer"
                       }
                    },
                    "fielddata": true
                 }
              }
           }
        }
     }
  }
  </code></pre>
  
  <p>Settings</p>
  
  <pre><code>    {
         "org-16-database": {
            "settings": {
               "index": {
                  "number_of_shards": "5",
                  "provided_name": "org-16-database",
                  "creation_date": "1521198435444",
                  "analysis": {
                     "normalizer": {
                        "my_normalizer": {
                           "filter": [
                              "lowercase"
                           ],
                           "type": "custom"
                        }
                     }
                  },
                  "number_of_replicas": "1",
                  "uuid": "lN-7iYloQWy7oaD3uMIYGQ",
                  "version": {
                     "created": "6010299"
                  }
               }
            }
         }
      }
  </code></pre>