Module vector search Future

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Vector Search Module - Future Enhancements

Scope

Forward-looking enhancements for vector search index performance, memory efficiency, distributed scaling, and integration hardening post-Wave D.

Design Constraints

• Preserve stable vector index and query interfaces for existing consumers (RAG, server).
• Keep search correctness deterministic under equivalent inputs and distance metrics.
• Maintain backward compatibility with existing serialized indices where feasible.
• Support graceful degradation when new features are unavailable.

Required Interfaces

Interface	Consumer	Notes
vector index creation and search	RAG retrieval, server endpoints	stable document ranking and similarity semantics
distance metric computation	query executors, rebuilding paths	consistent distance ordering across algorithms
index serialization/deserialization	persistent storage, distributed sync	deterministic index recovery and portability

Implementation Notes

Phase 5 (Continued) - Performance Hardening

Priority: High
Target: Q4 2026

• Complete SIMD distance kernel coverage (all supported architectures)
• Lock-free concurrent search structures (read-write separation)
• Adaptive index parameter tuning based on workload profiling
• Persistent index caching with validation checksums

Phase 6 (Extended) - Distributed Indexing

Priority: High
Target: Q1 2027

• Sharded index support (multi-node partition and query coordination)
• Cross-partition search and result merging
• Index replication and failure recovery
• Distributed query load balancing

Planned Enhancements - Algorithmic Diversity

Priority: Medium
Target: Q2 2027

• Product Quantization (PQ) for extreme-scale indices (100M+ vectors)
• Binary hash indices (BIN) for fast approximate search
• Learned index structures (trained tree indexes)
• Hybrid algorithm selection based on dimension/cardinality profile

Planned Enhancements - Integration Hardening

Priority: Medium
Target: Q2–Q3 2027

• Vector index observability (query latency histograms, cache hit rates)
• Automated index health checks and corruption detection
• Index compaction and defragmentation strategies
• Hot-reloading for parameter tuning without service interruption

Test Strategy

Implemented (Q3 2026)

• ✅ Unit tests for distance metrics and index operations
  • Test file: tests/vector_search/test_vector_search_highcardinality_stress.cpp
  • Coverage: HNSW/IVF operations, edge cases, stress scenarios
• ✅ Integration soak tests for durability and stability
  • Test file: tests/integration/test_vector_search_soak.cpp
  • Coverage: 60-second sustained throughput, concurrent recall, no corruption
• ✅ Benchmark suites for performance gating
  • Files: benchmarks/vector_search/bench_vector_search_dedicated_gates.cpp, benchmarks/ann/bench_vector_search.cpp
  • Coverage: insertion, search, concurrency, memory overhead

Planned (Q4 2026–Q1 2027)

• Distributed indexing correctness tests (cross-partition consistency)
• Large-scale index persistence tests (multi-GB indices)
• Parametric algorithm selection tests (auto-tuning validation)
• Memory pressure and degradation tests (out-of-core scenarios)

Performance Targets

Target	Current	Planned
Insert throughput (p95)	≥ 1 000 ops/sec	≥ 5 000 ops/sec (Phase 5 hardening)
Query latency p99 (k=10, 128-dim)	≤ 10 ms	≤ 5 ms (SIMD + lock-free)
Memory overhead	~30%	~15% (compression + PQ)
Concurrent query scaling	≥ 100 queries	≥ 1 000 queries (distributed)

Security / Reliability

Security Enhancements

• Index integrity validation (checksums for persisted indices)
• Query result authenticity (signed distance scores)
• Access control integration (per-index authorization checks)

Reliability Enhancements

• Automatic index repair on corruption detection
• Persistent write-ahead logs for index mutations
• Standby index replication and failover
• Circuit breaker patterns for degraded backends

Module Dependencies

Current Dependencies

• index — HNSW/IVF algorithm foundations
• storage — Planned integration for index persistence
• utils — SIMD distance helpers

Future Dependencies

• distributed — Cross-partition coordination (Phase 6)
• observability — Metrics and telemetry (Phase 6)
• security — Access control and validation (Phase 7)

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Wave Model Integration

This module contributes to Wave A → B → C → D execution. Enhancements are coordinated with the broader release pipeline and prioritized according to roadmap milestones.

See ROADMAP.md and ../../ROADMAP.md for release gating criteria.

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