CourseRetrieval-Augmented Generation: The Complete Course · Module 6: Search: Dense, Sparse, and Hybrid · part 46 of 95
Part 46 · Module 6: Search: Dense, Sparse, and Hybrid

Lab: Hybrid search on the filtered store

47 min read·13 Oct 2026
Module 6 · Lab · About 75 minutes · Needs: lessons 1 to 3 of this module, and the Module 5 lab (or the cells in Step 1)

What you are building

HOLLIN/SEARCH/, ON TOP OF HOLLIN/STORES/ 9 October rows 48 chunks dense leg FAISS green keyword leg BM25, same rows one Allow into both legs fusion alpha 0.8; RRF result set bar, signals, 3 of 10 measured and probed vs dense, 5 paths, 9 tests
The lab's piece: two legs over the same rows (blue), one filter handed to both (green), then fusion and the result set, measured and probed before it is committed.

On Friday 9 October Hollin's search has one leg: Module 5's filtered vector store. This lab adds hollin/search/ on top of it: a keyword leg over the same chunk rows, taking the same Allow filter; fusion at Lesson 2's alpha 0.8, with reciprocal rank fusion as the fallback; and Lesson 3's result set, from the refusal bar to three results from a pool of ten. Then you measure it against the dense-only baseline, probe every search path for leaks, write the tests and commit. No language model is called.

The rest of this course is yours to keep

This course is bought on its own, once, and stays readable afterwards, including the parts added to it later.