k-NN roadmap in light of Lucene 9.0

Hi everyone,

with release 9.0 Lucene introduced native ANN support (Lucene Change Log) based on small navigable worlds (~H~SNW). Elasticsearch 8.0 will include a new _knn_search endpoint (Add new kNN search endpoint by jtibshirani · Pull Request #79013 · elastic/elasticsearch · GitHub) leveraging the new Lucene capability.

Are there any plans on working on integrating the Lucene-native implementation in OpenSearch or OpenSearch kNN?

What’s your assessment of the situation?


Curious to see what others think as well. I feel like kNN is nice because of its simplicity and good accuracy with relatively small data sets. That being said it might be interesting if OpenSearch could allow users to specify whether they wanted to use Lucene’s ANN implementation or OpenSearches kNN.