pgvector HNSW compatibility profile

This directory vendors the dense vector and halfvec L2, inner-product, cosine, and L1 portions of pgvector’s upstream HNSW regression tests. The fixtures are derived from pgvector 0.8.3 (upstream commit represented by the repository’s certified reference snapshot) and retain pgvector’s PostgreSQL license in LICENSE.pgvector.

The only semantic adaptation is index DDL: source columns and query operators remain pgvector-owned, while USING hnsw and pgvector’s HNSW opclasses are replaced with USING pgcontext_hnsw and main-extension binding opclasses. This matches pgContext’s migration contract: applications keep their existing pgvector columns and SQL but explicitly build a pgContext index.

Run the profile against PostgreSQL 17 or 18 with vector and pgcontext installed. The runner enables the binding before executing the fixtures:

scripts/check-pgvector-regression-compat.sh

This is a bounded direct-serving profile. Native IVFFlat migration and setting translations are certified by the ownership-conversion and compatibility inventory gates rather than these HNSW-derived fixtures.