Provide support for combined keyword and semantic search using RRF.
The hybrid search in Atlas is performed like this - https://www.mongodb.com/docs/atlas/atlas-vector-search/tutorials/reciprocal-rank-fusion/

The request focused on implementing Hybrid search using the $unionWith operator as is given in the tutorial above.
There is a dedicated hybrid search MQL stage that's under consideration, but not prioritized yet. That dedicated hybrid search MQL stage only makes the process of writing this complex query but does not introduce any new functionality. The hybrid search exposed in LangChain allows us to provide the necessary syntactic ease of use to the users, as they would only interact with high level abstraction of LangChain and not need to learn complex MQL syntax

The Hybrid search retriever in LangChain shows up like this :
https://python.langchain.com/docs/integrations/vectorstores/elasticsearch/#example-approx-with-hybrid
https://python.langchain.com/docs/integrations/providers/pinecone/#pinecone-hybrid-search