elasticsearch - Return term frequency of a single field

Question

I have being trying to use facet to get the term frequency of a field. My query returns just one hit, so I would like to have the facet return the terms that have the most frequency in a particular field.

My mapping:

{
"mappings":{
    "document":{
        "properties":{
            "tags":{
                "type":"object",
                "properties":{
                    "title":{
                        "fields":{
                            "partial":{
                                "search_analyzer":"main",
                                "index_analyzer":"partial",
                                "type":"string",
                                "index" : "analyzed"
                            }
                            "title":{
                                "type":"string",
                                "analyzer":"main",
                                "index" : "analyzed"
                            }
                        },
                        "type":"multi_field"
                    }
                }
            }
        }
    }
},

"settings":{
    "analysis":{
        "filter":{
            "name_ngrams":{
                "side":"front",
                "max_gram":50,
                "min_gram":2,
                "type":"edgeNGram"
            }
        },

        "analyzer":{
            "main":{
                "filter": ["standard", "lowercase", "asciifolding"],
                "type": "custom",
                "tokenizer": "standard"
            },
            "partial":{
                "filter":["standard","lowercase","asciifolding","name_ngrams"],
                "type": "custom",
                "tokenizer": "standard"
            }
        }
    }
}

}

Test data:

 curl -XPUT localhost:9200/testindex/document -d '{"tags": {"title": "people also kill people"}}'

Query:

 curl -XGET 'localhost:9200/testindex/document/_search?pretty=1' -d '
{
    "query":
    {
       "term": { "tags.title": "people" }
    },
    "facets": {
       "popular_tags": { "terms": {"field": "tags.title"}}
    }
}'

This result

"hits" : {
   "total" : 1,
    "max_score" : 0.99381393,
    "hits" : [ {
    "_index" : "testindex",
    "_type" : "document",
    "_id" : "uI5k0wggR9KAvG9o7S7L2g",
    "_score" : 0.99381393, "_source" : {"tags": {"title": "people also kill people"}}
 } ]
},
"facets" : {
  "popular_tags" : {
  "_type" : "terms",
  "missing" : 0,
  "total" : 3,
  "other" : 0,
  "terms" : [ {
    "term" : "people",
    "count" : 1            // I expect this to be 2
   }, {
    "term" : "kill",
    "count" : 1
  }, {
    "term" : "also",
    "count" : 1
  } ]
}

}

The above result is not what I want. I want to have the frequency count be 2

"hits" : {
   "total" : 1,
   "max_score" : 0.99381393,
   "hits" : [ {
   "_index" : "testindex",
   "_type" : "document",
   "_id" : "uI5k0wggR9KAvG9o7S7L2g",
   "_score" : 0.99381393, "_source" : {"tags": {"title": "people also kill people"}}
} ]
},
"facets" : {
"popular_tags" : {
  "_type" : "terms",
  "missing" : 0,
  "total" : 3,
  "other" : 0,
  "terms" : [ {
    "term" : "people",
    "count" : 2            
  }, {
    "term" : "kill",
    "count" : 1
  }, {
    "term" : "also",
    "count" : 1
  } ]
 }
}

How do I achieve this? Is facet the wrong way to go?

Answer 1

A facet counts the documents, not the terms belonging to them. You get 1 because only one document contains that term, it doesn't matter how many times that happens. I'm not aware of an out of the box way to return the term frequency, the facet is not a good choice.
That information could be stored in the index if you enable the term vectors, but there's no way to read the term vectors from elasticsearch by now.