elasticsearch/elasticsearch — pull request #6740 by alexksikes (2014-07-04 19:27:38+00:00)
Title: More Like This Query: fetch text from all possible fields if none are specified

Items with no specified field now defaults to all the possible fields from the
document source. Previously, we had required 'fields' to be specified either
as a top level parameter or for each item. The default behavior is now similar
to the MLT API for each item.