How to make a Rasa chatbot search for answers with Haystack and QA

I think Haystack is awesome but when the Faiss vector index starts getting too large their default 'Flat' index is too slow. I think a lot of people miss that they can fix that using custom Faiss indexes, which are set using `faiss_index_factory_str` when initializing the index.

I built a big course on vector search (it's free), and more specific to this problem, an article covering these index factory strings and how to build good indexes with them - hopefully it's useful!

https://www.pinecone.io/learn/composite-indexes/

In a similar vein, we showed how to make Rasa search for answers using ZIR Semantic Search:

https://blog.zir-ai.com/semantic-search-helps-chatbots-answe...

There was a dramatic jump in recall (13->74%) and F1 (20->63%). I believe that neural search is the future for most search problems.