Match all query
The most simple query, which matches all documents, giving them all a _score of 1.0.
GET /_search{ "query": { "match_all": {} } }
The _score can be changed with the boost parameter:
GET /_search{ "query": { "match_all": { "boost" : 1.2 } } }
This is the inverse of the match_all query, which matches no documents.
GET /_search{ "query": { "match_none": {} } }