Elastic search, sort by number of documents a user has

Question

I have an index, every document belongs to a user.

I want to be able to sort in such a way so that the results return

• the first matching document of each user
• the second matching document of each user
• the third... etc

This would be to prevent one user to fill up the search results.

The only thing i could think of is to basically keep a counter in each document the user has and then sort on that counter. it would also mean that every time i delete or add a document i need to update all of the documents of the user.

Is there a better way of doing this?

Answer 1

Field collapsing may work for you. https://www.elastic.co/guide/en/elasticsearch/reference/current/collapse-search-results.html

If you collapse by userId, you can retrieve documents grouped by userId. And using inner_hits you can retrieve documents related to that user.