Unable to retrieve field value from Doc Values in nested function_score query

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1

Hi all,

We are using function_score query to sort search results. The score takes into account the value of a field in the indexed document. However, it appears the field value can not be properly retrieved from Doc Values, it always returns '0' although the actual value is otherwise.

Here I prepared some documents and query to illustrate the problem, you may try it out in CONSOLE.

As the example shows the field 'reward_factor' in the indexed document is populated with non zero value, however, when it's retrieved using doc['reward_factor'].value, it is alway '0'. Tried other ways to retrieve the value, such as _fields (as documented here), no success.

One thing maybe special here is that the function_score query is under a 'nested' query, in such case, are we not able to retrieve the field value? No documentation seems indicating so.

Much appreciated if someone could help with this.

Junjun

PS: Elasticsearch version: 5.1.1

2

hi,

I would say that the function_score is only applied on the nested documents, so the reward_factor is not accessible

see if it can helps:

bye,
Xavier

3

Thank you Xavier for your answer. It makes sense although I do wish there is a way to get the field value from parent docs. I guess I have a walk-around that is to include 'reward_factor' field in each of the nested subdocuments. Not very elegant, but it should work.
Cheers,
Junjun