Trouble with has_parent query containing scripted function_score

Question

I have two document types, in a parent-child relationship:

\"myParent\" : {
  \"properties\" : {
    \"weight\" : {
      \"type\" : \"double\"
    }
  }
}

         


        

Answer 1

I think the problem is that you are trying to score child documents based on a field in the parent document and that the function score should really be the other way round.

To solve the problem my idea would be to store the parent/child relation and the score with the child documents. Then you would filter for child documents and score them according to the weight in the child document.

An example:

"myParent" : {
    "properties" : {
        "name" : {
            "type" : "string"
        }
    }
}

"myChild" : {
    "_parent" : {
        "type" : "myParent"
    },
    "_routing" : {
        "required" : true
    },
    "properties": {
        "weight" : {
            "type" : "double"
        }
    }
}

Now you could use a has_parent filter to select all child documents that have a certain parent and then score them using the function score:

{
    "query": {
        "filtered": {
            "query": {
                "function_score" : {
                    "script_score" : {
                        "script" : "_score * doc['weight'].value"
                    }
                }
            },
            "filter": {
                "has_parent": {
                    "parent_type": "myParent",
                    "query": {
                        "term": {
                            "name": "something"
                        }
                    }
                }
            }
        }
    }
}

So if parent documents were blog posts and child comments, then you could filter all posts and score the comments based on weight. I doubt that scoring childs based on parents is possible though I might be wrong :)

Disclaimer: 1st post to stack overflow...