Expand description
Cold storage tier with Product Quantization (PQ) compression.
Vectors are encoded into compact PQ codes for massive storage reduction. A codebook of centroids is trained via k-means on representative data, then each vector is encoded as a sequence of centroid indices.
§Compression
With M=8 subspaces and K=256 centroids per subspace:
- Original D=768 vector: 768 × 4 bytes = 3,072 bytes
- PQ code: 8 × 1 byte = 8 bytes
- Compression ratio: 384×
§Asymmetric Distance Computation (ADC)
Query-to-code distance is computed without decoding: precompute query-to-centroid distances, then sum lookup table entries.
Structs§
- Cold
Entry 🔒 - A single entry in cold storage.
- Cold
Store - Cold store using PQ-encoded vectors.
- PqCodebook
- Product Quantization codebook.