Parent/child

gistfile1.txt

DELETE /myindex

PUT /myindex/
{
    "mappings": {
        "error" : {
         "_parent" : {
             "type" : "activitytype"
         }
        }
    }
}

PUT /myindex/activitytype/1
{
    "message": "I am a parent"
}

PUT /myindex/error/1?parent=1
{
    "message": "I am a child"
}

POST /myindex/activitytype/_search
{
  "query": {
    "has_child": {
      "type": "error",
      "query": {
        "match": {
          "_all": "child"
        }
      }
    }
  }
}