OpenSearch/docs/reference/mapping/fields.asciidoc

[[mapping-fields]]
== Meta-Fields

Each document has metadata associated with it, such as the `_index`, mapping
<<mapping-type-field,`_type`>>, and `_id` meta-fields.  The behaviour of some of these meta-fields
can be customised when a mapping type is created.

[float]
=== Identity meta-fields

[horizontal]
<<mapping-index-field,`_index`>>::

    The index to which the document belongs.

<<mapping-type-field,`_type`>>::

    The document's mapping type.

<<mapping-id-field,`_id`>>::

    The document's ID.

[float]
=== Document source meta-fields

<<mapping-source-field,`_source`>>::

    The original JSON representing the body of the document.

{plugins}/mapper-size.html[`_size`]::

    The size of the `_source` field in bytes, provided by the
    {plugins}/mapper-size.html[`mapper-size` plugin].

[float]
=== Indexing meta-fields

<<mapping-field-names-field,`_field_names`>>::

    All fields in the document which contain non-null values.

<<mapping-ignored-field,`_ignored`>>::

    All fields in the document that have been ignored at index time because of
    <<ignore-malformed,`ignore_malformed`>>.

[float]
=== Routing meta-field

<<mapping-routing-field,`_routing`>>::

    A custom routing value which routes a document to a particular shard.

[float]
=== Other meta-field

<<mapping-meta-field,`_meta`>>::

    Application specific metadata.


include::fields/field-names-field.asciidoc[]

include::fields/ignored-field.asciidoc[]

include::fields/id-field.asciidoc[]

include::fields/index-field.asciidoc[]

include::fields/meta-field.asciidoc[]

include::fields/routing-field.asciidoc[]

include::fields/source-field.asciidoc[]

include::fields/type-field.asciidoc[]
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00			`[[mapping-fields]]`
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			`== Meta-Fields`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			Each document has metadata associated with it, such as the `_index`, mapping
			<<mapping-type-field,`_type`>>, and `_id` meta-fields. The behaviour of some of these meta-fields
			`can be customised when a mapping type is created.`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`[float]`
			`=== Identity meta-fields`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			`[horizontal]`
			<<mapping-index-field,`_index`>>::

			`The index to which the document belongs.`

			<<mapping-type-field,`_type`>>::

Remove the top-level 'mapping type' section. (#54035) It seemed confusing for users that our top-level mapping page still had a prominent section named 'Mapping Type'. This PR reworks the docs to remove this reference and adds a note about types removal (similar to the note we added to other APIs like put mapping). 2020-03-23 18:34:23 -04:00			`The document's mapping type.`
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00
			<<mapping-id-field,`_id`>>::

			`The document's ID.`

Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`[float]`
			`=== Document source meta-fields`

Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			<<mapping-source-field,`_source`>>::

			`The original JSON representing the body of the document.`

Docs: Another bad asciidoc link 2015-08-15 12:22:22 -04:00			{plugins}/mapper-size.html[`_size`]::
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00
Docs: Prepare plugin and integration docs for 2.0 * Centralised plugin docs in docs/plugins/ * Moved integrations into same docs * Moved community clients into the clients section of the docs * Removed docs/community Closes #11734 Closes #11724 Closes #11636 Closes #11635 Closes #11632 Closes #11630 Closes #12046 Closes #12438 Closes #12579 2015-08-15 12:00:55 -04:00			The size of the `_source` field in bytes, provided by the
Docs: Another bad asciidoc link 2015-08-15 12:25:34 -04:00			{plugins}/mapper-size.html[`mapper-size` plugin].
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00
			`[float]`
			`=== Indexing meta-fields`

Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			<<mapping-field-names-field,`_field_names`>>::

			`All fields in the document which contain non-null values.`

Add a new `_ignored` meta field. (#29658) This adds a new `_ignored` meta field which indexes and stores fields that have been ignored at index time because of the `ignore_malformed` option. It makes malformed documents easier to identify by using `exists` or `term(s)` queries on the `_ignored` field. Closes #29494 2018-05-02 04:47:02 -04:00			<<mapping-ignored-field,`_ignored`>>::

			`All fields in the document that have been ignored at index time because of`
			<<ignore-malformed,`ignore_malformed`>>.

Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`[float]`
Remove usage of multi-types from the docs and added a page explaining type removal (#25543) Closes #25401 2017-07-05 06:30:19 -04:00			`=== Routing meta-field`
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00
			<<mapping-routing-field,`_routing`>>::

			`A custom routing value which routes a document to a particular shard.`

Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`[float]`
			`=== Other meta-field`
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			<<mapping-meta-field,`_meta`>>::
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`Application specific metadata.`
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00

Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`include::fields/field-names-field.asciidoc[]`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Add a new `_ignored` meta field. (#29658) This adds a new `_ignored` meta field which indexes and stores fields that have been ignored at index time because of the `ignore_malformed` option. It makes malformed documents easier to identify by using `exists` or `term(s)` queries on the `_ignored` field. Closes #29494 2018-05-02 04:47:02 -04:00			`include::fields/ignored-field.asciidoc[]`

Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			`include::fields/id-field.asciidoc[]`

Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`include::fields/index-field.asciidoc[]`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`include::fields/meta-field.asciidoc[]`
Index field names of documents. The `exists` and `missing` filters need to merge postings lists of all existing terms, which can be very costly, especially on high-cardinality fields. This commit indexes the field names of a document under `_field_names` and reuses it to speed up the `exists` and `missing` filters. This is only enabled for indices that are created on or after Elasticsearch 1.3.0. Close #5659 2014-05-20 11:34:00 -04:00
Docs: Refactored the mapping meta-fields docs 2015-07-19 19:24:29 -04:00			`include::fields/routing-field.asciidoc[]`
Migrated documentation into the main repo 2013-08-28 19:24:34 -04:00
Docs: Mapping docs completely rewritten for 2.0 2015-08-06 11:24:29 -04:00			`include::fields/source-field.asciidoc[]`

			`include::fields/type-field.asciidoc[]`