Function create_hnsw_index_sql 

pub fn create_hnsw_index_sql(
    table: &str,
    ops_class: &str,
    m: Option<usize>,
    ef_construction: Option<usize>,
) -> String

Returns the CREATE INDEX statement for an HNSW index.

The operator class is chosen based on the distance metric:

• Cosine → vector_cosine_ops
• L2 → vector_l2_ops
• InnerProduct → vector_ip_ops

Parameters

• table: table name
• ops_class: one of vector_cosine_ops, vector_l2_ops, vector_ip_ops
• m: HNSW m parameter (max connections per layer). None uses the PG default (16).
• ef_construction: HNSW build-time search width. None uses the PG default (64).