Hierarchical Navigable Small World (HNSW) indexing is a graph-based approach that significantly enhances search efficiency in high-dimensional vector spaces. By structuring data in a navigable small-world graph, HNSW enables rapid nearest-neighbor searches, making it a preferred choice for large-scale vector retrieval tasks.

To configure document store to use HNSW index, post a request to the `/api/kb/<storeName>/index` endpoint and specify `HNSW` as the value of the `type` property:

http request
 POST /api/kb/<storeName>/index

 {
    "type": "HNSW",
    "spaceName": "COSINE",
    "efConstruction": 200,
    "efSearch": 50,
    "m": 16
 }

Technically, all properties other than `type` in the payload above can be omitted, as they use the default values.