Elasticsearch nested nested keyword search

nested-nested-keyword.json

# Create new index
PUT test2
{
  "mappings": {
    "properties": {
      "relations": {
        "type": "nested",
        "properties": {
          "parts": {
            "type": "nested",
            "properties": {
              "ACL": {
                "type": "keyword"
              }
            }
          }
        }
      }
    }
  }
}

# Index first document: red
PUT test2/_doc/1
{
  "relations": [
   {
     "parts": [
       {
         "ACL": "red" 
       }
      ]
   }
  ]
}

# Index second document: RED
PUT test2/_doc/2
{
  "relations": [
   {
     "parts": [
       {
         "ACL": "RED" 
       }
      ]
   }
  ]
}

# Index third document: rEd
PUT test2/_doc/3
{
  "relations": [
   {
     "parts": [
       {
         "ACL": "TEST" 
       }
      ]
   }
  ]
}

# Search for "RED" - finds only first document.
GET test2/_search
{
  "query": {
    "nested": {
      "path": "relations",
      "query": {
        "nested": {
          "path": "relations.parts",
          "query": {
            "term": {
              "relations.parts.ACL": {
                "value": "RED"
              }
            }
          }
        }
      }
    }
  }
}

# Search using multiple terms - finds 2 out of 3 documents.
GET test2/_search
{
  "query": {
    "nested": {
      "path": "relations",
      "query": {
        "nested": {
          "path": "relations.parts",
          "query": {
            "terms": {
              "relations.parts.ACL": [
                "RED",
                "red"
              ]
            }
          }
        }
      }
    }
  }
}

# Create new index
PUT test3
{
  "mappings": {
    "properties": {
      "relations": {
        "properties": {
          "parts": {
            "properties": {
              "ACL": {
                "type": "keyword"
              }
            }
          }
        }
      }
    }
  }
}

# Index first document: red
PUT test3/_doc/1
{
  "relations": {
    "parts": {
       "ACL": "red" 
    }
  }
}

# Index second document: RED
PUT test3/_doc/2
{
  "relations": {
    "parts": {
       "ACL": "RED" 
    }
  }
}

# Index third document: rEd
PUT test3/_doc/3
{
  "relations": {
    "parts": {
       "ACL": "rEd" 
    }
  }
}

# Check 3 documents exist
GET test3/_search

# Search for "RED" - finds only first document.
GET test3/_search
{
  "query": {
    "terms": {
      "relations.parts.ACL": [
        "RED"
      ]
    }
  }
}