elastic/elasticsearch

Add support for collapse sort to specify how to sort groups relative to each other

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#45,646 opened on Aug 16, 2019

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 (26 comments) (31 reactions) (0 assignees)Java (25,882 forks)batch import
:Search Relevance/Ranking>enhancementTeam:Search Relevancehelp wantedhigh hanging fruit

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Description

This is a feature request.

At the moment, field collapsing will use the same scoring as the main query to choose the document that will appear in the main search results hits.

it would be good to have a score for the main query but another score to choose which one is going to be chosen within the field-collapsed set.

We can use inner_hit to sort the inner hits but this does not change the top document that has been chosen in the main hits. We can then manually choose the inner_hit..hits.hits[0] instead of the top hits.

I think the collapse feature would benefit from having a collapse_sort that will define the hit that will be chosen at the top level.

Thanks

Contributor guide

Research direction
Research how Elasticsearch currently implements field collapsing and sorting. Look at the codebase for collapse and sort parameters. Propose a design for adding a `collapse sort` parameter that allows specifying a sort order for choosing the top collapsed document.
Tech stack
javaelasticsearch
Domain
backendapi
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaElasticsearch internalsREST API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35