The community member is asking if there is a way to create a keyword-based retriever like BM25Retriever based on an existing index, as they have already embedded and ingested their documents into a Postgres vectorstore.
In the comments, another community member suggests that the custom retrieval example in the documentation shows an example of using a keyword-based retriever. However, the original poster then asks how to create a keyword-based retriever based on the existing index.
Another community member responds with a potential solution, suggesting that the user can use the nodes from the existing index to create a keyword index using the SimpleKeywordTableIndex class.
There is no explicitly marked answer in the provided information.
Is there a way to create a keyword based retriever like BM25Retriever based on an existing index? I have already embedded and ingested my documents into a postgres vectorstore and want to create a retriever from an already existing index.
