5 factors should be considered when selecting the Vector Search

Here are 5 factors that should be considered when selecting the Vector Search/Index algorithms.

Data size:

  • For data sizes under 100K, a brute-force solution utilizing a FLAT index is sufficiently efficient.

  • Advanced algorithms may not offer significant speed improvements in such scenarios.

Speed-Recall trade-off:

  • When an exact match is important then brute force is the right solution

  • Significant query latency reduction is achievable with a minor sacrifice in recall.

Memory limitation:

  • Some algorithms like HNSW are memory-hungry.

  • Scalar and Product Quantization significantly reduces storage consumption, at the expense of the Recall.


  • Usually moving from CPU to GPU provides a speed boost

  • Not all algorithms are optimized for GPU

Building/Indexing time:

  • Sometimes the building/indexing time is crucial.

  • IVF has a shorter indexing time compared to HNSW.