原文地址: https://www.elastic.co/guide/en/elasticsearch/reference/7.7/mapping-fields.html, 原文档版权归 www.elastic.co 所有

Meta-Fieldsedit

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

Identity meta-fieldsedit

_index

The index to which the document belongs.

_type

The document’s mapping type.

_id

The document’s ID.

Document source meta-fieldsedit

_source
The original JSON representing the body of the document.
_size
The size of the _source field in bytes, provided by the mapper-size plugin.

Indexing meta-fieldsedit

_field_names
All fields in the document which contain non-null values.
_ignored
All fields in the document that have been ignored at index time because of ignore_malformed.

Routing meta-fieldedit

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

Other meta-fieldedit

_meta
Application specific metadata.