* Remove the _all metadata field
This change removes the `_all` metadata field. This field is deprecated in 6
and cannot be activated for indices created in 6 so it can be safely removed in
the next major version (e.g. 7).
This change disables the _all meta field by default.
Now that we have the "all-fields" method of query execution, we can save both
indexing time and disk space by disabling it.
_all can no longer be configured for indices created after 6.0.
Relates to #20925 and #21341Resolves#19784
* 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#11734Closes#11724Closes#11636Closes#11635Closes#11632Closes#11630Closes#12046Closes#12438Closes#12579
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
Jim Ferenczi
Clinton Gormley
Lee Hinman
Adrien Grand
Ryan Ernst