index

The index option controls how field values are indexed and, thus, how they are searchable. It accepts three values:

no

Do not add this field value to the index. With this setting, the field will not be queryable.

not_analyzed

Add the field value to the index unchanged, as a single term. This is the default for all fields that support this option except for string fields. not_analyzed fields are usually used with term-level queries for structured search.

analyzed

This option applies only to string fields, for which it is the default. The string field value is first analyzed to convert the string into terms (e.g. a list of individual words), which are then indexed. At search time, the query string is passed through (usually) the same analyzer to generate terms in the same format as those in the index. It is this process that enables full text search.

For example, you can create a not_analyzed string field with the following:

PUT /my_index
{
  "mappings": {
    "my_type": {
      "properties": {
        "status_code": {
          "type": "string",
          "index": "not_analyzed"
        }
      }
    }
  }
}