Jim Ferenczi 17b9baf5fd Clarify pure wilcard matching with query_string (#26814)
In 5.x pure wildcard queries `*` in `query_string` are rewritten to `exists` query for efficiency.
Though this introduced a change in the document that match such queries because
`exists` query also return documents with an empty value for the field.
This change clarifies this behavior for 5.x and beyond.

Closes #26801

* review
2017-10-04 09:55:26 +02:00
..
2017-03-30 22:26:10 -04:00