When creating an app for multiple users, obviously I need memory to be individual for each user, but what about retrievers and rerankers, and if I can use them for multiple users at the same time is there latency or not, and if there is latency what is in your experience good balance for sharing retrievers and rerankers

if i ran workflow in a task asyncio.create_task(workflow.run()) how do i safely cancel it

Hello, I was using Postgres with pgvector for hybrid search with QueryFusionRetriever version for even better results.
Now I'm trying to transition to pgvector.rs for faster performance but even though their documentation states there is dense and sparse search options I can't seem to find those options in llama index implementation of Vector store.
Is there a way to use those options with llama index especially with QueryFusionRetriever if possible