Vector Store: Provide distance functions as scalar functions about crate HOT 3 OPEN

SELECT * FROM items ORDER BY embedding <-> '[3,1,2]' LIMIT 5;

If the result isn't used, this would likely just be a slower version of the existing knn_match

from crate.

I think this is the same/similar as #15768? At the moment, we use Euclidian Distance per default, but users might want to have Cosine and Dot Product due to a different approach to calculate the similarity.

from crate.

I think this is the same/similar as #15768?

Here we track actual distance support. Similarity, is F(distance) with values in range 0-1. Actual distance also can be used to evaluate similarity, see pg_vector example above, different use case.

I think #15768 is actually duplicate of #14801.

However, #14801 has been closed with "only euclidean based" (comment), so #15768 covers remaining (cosine, dot product) based similarities

from crate.