Ben

[doc](https://www.elastic.co/guide/en/elasticsearch/guide/master/grandparents.html) Same as parent just need to pass in a routing field so everything is on the same shard.

Use case is for hiding elements initially when the ref element is being loaded.

https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/#up._S_[%3Cidentifier%3E]