OpenAI's demo day showcased various Retrieval-Augmented Generation (RAG) experiments, highlighting that different retrieval techniques suit different problems. Their study demonstrated the efficacy of methods like distance-based vector database retrieval, which uses cosine similarity for document matching, and query transformations such as LangChain's Multi-query retriever and HyDE, which improve retrieval by generating multiple perspectives or hypothetical documents. Routing questions appropriately across multiple datastores, including SQL databases, is crucial, and LangChain supports such routing with LLMs. Building the index with optimal chunk sizes and employing post-processing techniques like re-ranking and classification can enhance retrieval performance. OpenAI's experiments underscore the importance of evaluation to ensure effective RAG approaches, with tools like LangSmith available to support this process.