Custom plugin for Elasticsearch to change the default relevancy

Question

I am currently using Elasticsearch and there are few things I have noticed about the ranks of the search results, which led me to think about whether there is a way to create plugins/script for ES, which can be used to modify the current scoring algorithm?

Answer 1

You can either write a custom Java plugin for that, use function score queries, or scripted similarity (which just came out this week).

If you can I would use the two later methods; writing a custom plugin should only be required very rarely.

Answer 2

You can refer to the blog A Gentle Intro to Function Scoring which describes ranking of videos on a website using a combination of textual relevance and the videos popularity on a site.

To modify the scoring algorithm the Elasticsearch provides script_score, function_score and Decay Function.