When doing a hybrid search using a query
and a knn
clause using the _search api, the combined document score is the sum of both scores. What I am unable to find in the docs is how the knn and match scores relate? Are they comparable?
As an extreme example. Lets say a good score for the "match" part is a score of 5
and a good score for the "knn" part is 0.5
, then the sum of both doesn't add much value. Its overwhelmingly just the "match" part that determines the overal score.
Ofcourse you can boost the knn score to make it a more significant factor of the scores, but are there any guidelines on how competitive knn scores are compared to a standard text matching query and how much you will need to boost them (or the other way around)?