OpenSearch/docs/plugins/mapper-size.asciidoc

[[mapper-size]]
=== Mapper Size Plugin

The mapper-size plugin provides the `_size` meta field which, when enabled,
indexes the size in bytes of the original
{ref}/mapping-source-field.html[`_source`] field.

[[mapper-size-install]]
[float]
==== Installation

This plugin can be installed using the plugin manager:

[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin install mapper-size
----------------------------------------------------------------

The plugin must be installed on every node in the cluster, and each node must
be restarted after installation.

[[mapper-size-remove]]
[float]
==== Removal

The plugin can be removed with the following command:

[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin remove mapper-size
----------------------------------------------------------------

The node must be stopped before removing the plugin.

[[mapper-size-usage]]
==== Using the `_size` field

In order to enable the `_size` field, set the mapping as follows:

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

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>
    }
  }
}
--------------------------
// CONSOLE
// TEST[continued]

<1> Querying on the `_size` field