Elastic Search Terms Facet Weirdness

gistfile1.sh

# Create Index
curl -XPUT 'http://localhost:9200/survey/' -d '{
    "number_of_shards": 1,
    "number_of_replicas": 0
}'

# Put mapping
curl -XPUT 'http://localhost:9200/survey/response/_mapping' -d '{
    "response" : {
        "_source" : {
            "compression" : true
        },
        "properties" : {
            "impression" : {
                "type": "object",
                "properties" : {
                    "topic" : { 
                        "type":"string"
                    },
                    "sentiment" : { 
                        "type":"string"
                    }
                }
            }
        }       
    }
}'

# Index documents
curl -XPUT 'http://localhost:9200/survey/response/1' -d '{
    "user" : "napoleon",        
    "impression" : [ { "topic" : "checkout", "sentiment" : "negative" }, { "topic" : "other", "sentiment" : "positive"}]
}'

curl -XPUT 'http://localhost:9200/survey/response/2' -d '{
    "user" : "snowball",        
    "impression" : [ { "topic" : "colour", "sentiment" : "positive" }, { "topic" : "other", "sentiment" : "negative"}]
}'

curl -XPUT 'http://localhost:9200/survey/response/3' -d '{
    "user" : "squealer",        
    "impression" : [ { "topic" : "size", "sentiment" : "positive" }, { "topic" : "other", "sentiment" : "positive"}]
}'

# This query works but produces wrong results because I forgot to set the field type to nested
curl -XGET 'http://localhost:9200/survey/response/_search' -d '{
    "size" : 0,
    "facets": {
        "p": {
          "terms": {
            "field": "impression.topic",
            "size": 10
          }
       }
    },
    "query": {
        "bool": {
          "must": [
            {
              "term": {
                "impression.topic": "colour"
              }
            },
            {
              "term": {
                "impression.sentiment": "negative"
              }
            }
          ]
        }
      }
}'

# Update mapping to add an identical field with nested type
curl -XPUT 'http://localhost:9200/survey/response/_mapping' -d '{
    "response" : {
        "_source" : {
            "compression" : true
        },
        "properties" : {
            "impression" : {
                "type": "object",
                "properties" : {
                    "topic" : { 
                        "type":"string"
                    },
                    "sentiment" : { 
                        "type":"string"
                    }
                }
            },
            "nested_impression" : {
                "type": "nested",
                "properties" : {
                    "topic" : { 
                        "type":"string"
                    },
                    "sentiment" : { 
                        "type":"string"
                    }
                }
            }
        }       
    }
}'

# Use the update API to copy the old field to the new field and re-index the document
curl -XPOST 'http://localhost:9200/survey/response/1/_update' -d '{
    "script" : "ctx._source.nested_impression = ctx._source.impression"
}'

curl -XPOST 'http://localhost:9200/survey/response/2/_update' -d '{
    "script" : "ctx._source.nested_impression = ctx._source.impression"
}'

curl -XPOST 'http://localhost:9200/survey/response/3/_update' -d '{
    "script" : "ctx._source.nested_impression = ctx._source.impression"
}'


# This facet returns "missing" fields
curl -XGET 'http://localhost:9200/survey/response/_search' -d '{
  "size" : 0,
  "facets": {
    "p": {
      "terms": {
        "field": "nested_impression.topic",
        "size": 10
      }
    }
  },
  "query": {
    "nested": {
      "path": "nested_impression",
      "query": {
        "bool": {
          "must": [
            {
              "term": {
                "nested_impression.topic": "colour"
              }
            },
            {
              "term": {
                "nested_impression.sentiment": "positive"
              }
            }
          ]
        }
      }
    }
  }
}'

# Yet the query returns the correct document. 
curl -XGET 'http://localhost:9200/survey/response/_search' -d '{
    "query": {
    "nested": {
      "path": "nested_impression",
      "query": {
        "bool": {
          "must": [
            {
              "term": {
                "nested_impression.topic": "colour"
              }
            },
            {
              "term": {
                "nested_impression.sentiment": "positive"
              }
            }
          ]
        }
      }
    }
  }
}'