[[mapper]]
== Mapper Plugins

Mapper plugins allow new field datatypes to be added to Elasticsearch.

[float]
=== Core mapper plugins

The core mapper plugins are:

<<mapper-size>>::

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-murmur3>>::

The mapper-murmur3 plugin allows hashes to be computed at index-time and stored
in the index for later use with the `cardinality` aggregation.

include::mapper-size.asciidoc[]
include::mapper-murmur3.asciidoc[]