More_like_this not using nested fields?

[ndtreviv (Nathan Trevivian)]

I want to use the more like this query type to find similar documents without having to construct a bool. I like the minimum_should_match as a percent to identify %-similar documents.

My document has lots of nested fields. For example, I have a nested document specified in the mapping like this:

...
      "screenshot": {
        "type": "nested",
        "properties": {
          "md5": {
            "type": "keyword",
            "store": true
          },
          "pdq": {
            "type": "keyword",
            "store": true
          },
          "pdqId": {
            "type": "long"
          },
          "src": {
            "type": "text",
            "term_vector": "yes"
          },
          "extension": {
            "type": "keyword",
            "store": true
          },
          "mimeType": {
            "type": "keyword",
            "store": true
          }
        }
      },
...

I really want the src field to be used in MLT queries, but my tests indicate that it isn't.

How can I make that happen? Do I need to have include_in_root on the mapping for that field to make that happen?

Thanks for any help offered!