PostgreSQL - Making Double Bookings Impossible
Every hotel reservation system starts with the same line of code: SELECT 1 FROM reservation WHERE room_id = $1 AND check_out > $2 AND check_in < $3; -- no rows?...
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Inference Engineering - Part 1: How a Model Gets Made
I kept running into large language model (LLM) systems and finding that I could use them without understanding them. That is an uncomfortable place to be: you end up a...
Production RAG - Part 9: Splitting an Answer into Claims
Part 7 argued that a groundedness gate has to score atomic claims and take the minimum, because a five-sentence answer with one fabrication averages out to a passing s...
Production RAG - Part 8: Evaluation and Operations
Seven posts of machinery, and none of it is trustworthy until you can answer one question: how do you know it works? RAG systems are unusually hostile to intuition her...
Production RAG - Part 7: Grounded Generation
Retrieval can succeed completely and the answer can still be wrong. The model receives five relevant chunks and asserts a sixth thing that none of them support — a pla...
Production RAG - Part 6: Entities and Knowledge Graphs
At some point in every RAG project, a category of question stops working and no amount of tuning fixes it. Better chunking does not help. A stronger reranker does not ...
Production RAG - Part 5: Images and Multimodal Retrieval
Text retrieval works because both sides of the comparison are text living in one embedding space. An image breaks that symmetry, and the way you restore it is one of t...
Production RAG - Part 4: Hybrid Search, Fusion and Reranking
Ask a RAG system “how do I shut down an instance” and keyword search returns nothing useful, because the documentation says “halt” and “stop”. Ask it about CEAMVCSRE31...
Production RAG - Part 3: Chunking for Retrieval
A chunk is the smallest thing retrieval can return. You never get half a chunk, and never a chunk plus a bit of its neighbour. Whatever boundaries you draw at ingestio...
Production RAG - Part 2: Extracting Trustworthy Text from PDFs
A PDF is not a document in any structured sense. Rooted in PostScript, it is a list of drawing instructions: place this glyph at these coordinates, fill this rectangle...
