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Notes from building RosalindDB
Architecture, benchmarks, and the occasional post-mortem. We write up decisions in public so the project's reasoning is reviewable, not just its code.
May 22, 2026 · FAISS · indexing · recall · engineering
We swapped IVF+PQ for IVFFlat and got 4× recall back
IVF+PQ ceilinged out at recall@10 = 0.65 on a 100k SIFT benchmark, even with exhaustive probing. IVFFlat hit 0.99. Here is the math and what we gave up.
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May 22, 2026 · architecture · design · object-storage · FAISS · S3
Object-storage-first: why our query DP has no authoritative state
Most vector databases assume the index lives in cluster RAM. For cold and bursty workloads that's the wrong shape — here's the one we picked instead.
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