Asked about Running vector search in Postgres
How do you know your vector index is returning the right results?
An answer that works
Measure recall against exact search on a sample of real queries: run each with and without the index and see what fraction of the true top results the index returns. Then tune the search settings until recall is acceptable at your latency target.
Then they push further
Recall is high but retrieval quality is still poor. Why?
Index recall only says the index agrees with exact search. If exact search itself returns the wrong chunks, the problem is the embeddings, chunking or query, and needs a retrieval eval with labelled relevant chunks.
What gets marked up
Strong answers separate index recall from retrieval quality. Candidates who conflate them are marked down.
Reading an answer is not being able to give one. The section that teaches this is Running vector search in Postgres, 5 hours of Vector databases.
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