Elasticsearch is an amazing tool but the documentation does not always give that much help and advice on how to get going with it. Today was more_like_this (or mlt for sure) day so I thought I’d give a “get going” example.  It isn’t that complex except that the default settings are likely to return no results if you have a small data set. That’s why here I have the minimum values turned down to one, so that if there is any match you will get some results. Once you know you have a working query you can then start to turn the requirements back up or to the defaults.

{
  "query" : {
    "more_like_this" : {
      "like_text" : "testing",
      "min_term_freq" : 1,
      "min_doc_freq" : 1
    }
  }
}