Each document has metadata associated with it, such as the _index
and _id metadata fields. The behavior of some of these metadata
fields can be customized when a mapping is created.
Identity metadata fields
Document source metadata fields
-
_source - The original JSON representing the body of the document.
-
_size -
The size of the
_sourcefield in bytes, provided by themapper-sizeplugin.
Doc count metadata field
-
_doc_count - A custom field used for storing doc counts when a document represents pre-aggregated data.
Indexing metadata fields
-
_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 metadata field
-
_routing - A custom routing value which routes a document to a particular shard.