[[mapping-size-field]]
=== `_size` field

The `_size` field, when enabled, indexes the size in bytes of the original
<<mapping-source-field,`_source`>>. In order to enable it, set
the mapping as follows:

[source,js]
--------------------------
PUT my_index
{
  "mappings": {
    "my_type": {
      "_size": {
        "enabled": true
      }
    }
  }
}
--------------------------
// AUTOSENSE

The value of the `_size` field is accessible in queries, aggregations, scripts,
and when sorting:

[source,js]
--------------------------
# Example documents
PUT my_index/my_type/1
{
  "text": "This is a document"
}

PUT my_index/my_type/2
{
  "text": "This is another document"
}

GET my_index/_search
{
  "query": {
    "range": {
      "_size": { <1>
        "gt": 10
      }
    }
  },
  "aggs": {
    "Sizes": {
      "terms": {
        "field": "_size", <2>
        "size": 10
      }
    }
  },
  "sort": [
    {
      "_size": { <3>
        "order": "desc"
      }
    }
  ],
  "script_fields": {
    "Size": {
      "script": "doc['_size']"  <4>
    }
  }
}
--------------------------
// AUTOSENSE

<1> Querying on the `_size` field
<2> Aggregating on the `_size` field
<3> Sorting on the `_size` field
<4> Accessing the `_size` field in scripts (inline scripts must be <<enable-dynamic-scripting,enabled>> for this example to work)

