elasticsearch/docs/reference/mapping/fields/size-field.asciidoc

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

The `_size` field allows to automatically index the size of the original
`_source` indexed. By default, it's disabled. In order to enable it, set
the mapping to:

[source,js]
--------------------------------------------------
{
    "tweet" : {
        "_size" : {"enabled" : true}
    }
}
--------------------------------------------------