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3da738e5db
Now that the `fields` option allows fetching metadata fields, we can support loading the new `_tier` metadata field. Relates to #63569 and #68135.
85 lines
1.9 KiB
Text
85 lines
1.9 KiB
Text
[[mapping-fields]]
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== Metadata fields
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Each document has metadata associated with it, such as the `_index`
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and `_id` metadata fields. The behavior of some of these metadata
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fields can be customized when a mapping is created.
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[discrete]
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=== Identity metadata fields
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[horizontal]
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<<mapping-index-field,`_index`>>::
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The index to which the document belongs.
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<<mapping-id-field,`_id`>>::
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The document's ID.
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[discrete]
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=== Document source metadata fields
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<<mapping-source-field,`_source`>>::
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The original JSON representing the body of the document.
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{plugins}/mapper-size.html[`_size`]::
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The size of the `_source` field in bytes, provided by the
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{plugins}/mapper-size.html[`mapper-size` plugin].
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[discrete]
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=== Doc count metadata field
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<<mapping-doc-count-field,`_doc_count`>>::
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A custom field used for storing doc counts when a document represents pre-aggregated data.
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[discrete]
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=== Indexing metadata fields
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<<mapping-field-names-field,`_field_names`>>::
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All fields in the document which contain non-null values.
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<<mapping-ignored-field,`_ignored`>>::
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All fields in the document that have been ignored at index time because of
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<<ignore-malformed,`ignore_malformed`>>.
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[discrete]
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=== Routing metadata field
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<<mapping-routing-field,`_routing`>>::
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A custom routing value which routes a document to a particular shard.
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[discrete]
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=== Other metadata field
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<<mapping-meta-field,`_meta`>>::
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Application specific metadata.
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<<mapping-tier-field,`_tier`>>::
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The current data tier preference of the index to which the document belongs.
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include::fields/doc-count-field.asciidoc[]
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include::fields/field-names-field.asciidoc[]
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include::fields/ignored-field.asciidoc[]
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include::fields/id-field.asciidoc[]
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include::fields/index-field.asciidoc[]
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include::fields/meta-field.asciidoc[]
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include::fields/routing-field.asciidoc[]
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include::fields/source-field.asciidoc[]
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include::fields/tier-field.asciidoc[]
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