ignore_above

Strings longer than the ignore_above setting will not be indexed or stored. For arrays of strings, ignore_above will be applied for each array element separately and string elements longer than ignore_above will not be indexed or stored.

Note

All strings/array elements will still be present in the _source field, if the latter is enabled which is the default in Elasticsearch.

Note

In columnar index modes, ignore_above has no effect. Columnar _source is reconstructed from doc values, so a dropped value would be lost entirely; every value is stored regardless of length, whether or not the field is indexed. This covers the field-level parameter, the index.mapping.ignore_above setting, and index-mode defaults. The parameter is still accepted and echoed back by GET _mapping, over-limit values remain searchable and retrievable, and the field is not added to _ignored. Because nothing is dropped, ignore_above no longer shields you from Lucene's term byte-length limit: a value longer than 32766 bytes fails the indexing request. Columnar indices created before 9.6 keep the previous behavior.

				PUT my-index-000001
					{
  "mappings": {
    "properties": {
      "message": {
        "type": "keyword",
        "ignore_above": 20
      }
    }
  }
}
				PUT my-index-000001/_doc/1
					{
  "message": "Syntax error"
}
				PUT my-index-000001/_doc/2
					{
  "message": "Syntax error with some long stacktrace"
}
				GET my-index-000001/_search
					{
  "aggs": {
    "messages": {
      "terms": {
        "field": "message"
      }
    }
  }
}
  1. This field will ignore any string longer than 20 characters.
  2. This document is indexed successfully.
  3. This document will be indexed, but without indexing the message field.
  4. Search returns both documents, but only the first is present in the terms aggregation.
Tip

The ignore_above setting can be updated on existing fields using the update mapping API.

Outside columnar index modes, this option is also useful for protecting against Lucene’s term byte-length limit of 32766.

Note

The value for ignore_above is the character count, but Lucene counts bytes. If you use UTF-8 text with many non-ASCII characters, you may want to set the limit to 32766 / 4 = 8191 since UTF-8 characters may occupy at most 4 bytes.