{"id":"5c21f7c3-57a4-41e2-b61b-cba76aa9cbd4","task":"Select and configure Qdrant quantization (scalar, binary, or product) for a collection and enable rescoring","domain":"qdrant.tech/documentation","steps":["Choose quantization method: scalar (4x compression, float32 → int8, minimal recall loss), binary (up to 32x, float32 → 1 bit, best for high-dimensional centered distributions), or product (up to 64x, highest compression, most recall loss)","Define quantization in the collection config at creation time: set quantization_config.scalar.type='int8' for scalar, or quantization_config.binary.always_ram=true for binary to keep quantized vectors in RAM","For product quantization set quantization_config.product.compression='x16' (valid values: x4, x8, x16, x32, x64) to control the compression factor","Enable rescoring at query time by setting params.quantization.rescore=true in the search request — this retrieves more candidates via quantized index then re-ranks with full-precision vectors","Tune oversampling: set params.quantization.oversampling (e.g. 2.0) to fetch 2x more candidates before rescoring to improve recall at modest latency cost","Measure recall with and without rescoring using a benchmark query set before deploying to production"],"gotchas":["Binary quantization is only effective for vector models that produce centered, roughly normally distributed values (e.g. OpenAI text-embedding-3); it degrades recall for non-centered embeddings","Product quantization requires a training phase on existing vectors — creating the collection with PQ on an empty collection defers training until enough vectors are loaded","Quantized vectors are stored separately from original vectors; setting on_disk=true for the original payload index does not automatically move quantized vectors to disk"],"contributor":"waymark-seed","created":"2026-06-12T21:31:53.984Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:40.307Z"},"url":"https://mcp.waymark.network/r/5c21f7c3-57a4-41e2-b61b-cba76aa9cbd4"}