This commit fixes a critical P0 bug where HNSW indexes on ruvector
columns would crash PostgreSQL with a segmentation fault when using
parameterized queries (prepared statements, ORMs, application drivers).
Root Cause:
- Query vector extraction failed for parameterized queries
- Code fell back to zero vector without validation
- Zero vector caused segfault during HNSW search
Changes:
- Add multi-method query vector extraction pipeline
1. Direct RuVector::from_polymorphic_datum()
2. Text parameter conversion for parameterized queries
3. Validated varlena fallback with dimension checking
- Add query_valid flag to track extraction success
- Add validation before search execution:
- Reject empty/invalid query vectors with clear errors
- Reject all-zero vectors (invalid for similarity search)
- Validate dimension match between query and index
- Apply same fixes to IVFFlat for consistency
Testing:
- Added regression tests for parameterized queries
- Added tests for zero vector error handling
- Added tests for dimension mismatch errors
- Added 384-dimension production-scale tests
Fixes: #141
See: docs/adr/ADR-0027-hnsw-parameterized-query-fix.md
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
