Module process Roadmap

Process Module Roadmap

Current Status

Production-capable process modeling runtime with hardened edge-case behavior, unified diagnostics framework, and bounded resource constraints for process model lifecycle operations, multi-format import/export, linking, and process retrieval/RAG support surfaces.

Milestone: All Phase 1-6 deliverables complete (High-Churn Hardening Initiative). Module ready for production deployment with explicit concurrency, determinism, and diagnostics contracts.

• hardening process edge-case behavior across import/parsing and linking transitions (Target: Q3 2026)
• benchmark stabilization for process import/retrieval/mining hot paths (Target: Q3 2026)
• diagnostics consistency for model validation and retrieval incident classes (Target: Q3 2026)

Completed Initiatives

High-Churn Hardening Initiative (Phases 1-6) - COMPLETE ✓

All phases completed 2026-08-06. See detailed breakdown below.

Implementation Phases (Completed 2026-08-06)

Phase 1: Design & API Contract ✓ COMPLETE

Objective: Formalize API contracts for determinism, concurrency, and extended diagnostics under high model churn scenarios.

Deliverables:

• include/process/process_concurrency_contract.h – Thread-safety guarantees per layer with complete Doxygen documentation
• include/process/process_determinism_spec.h – Determinism and conflict resolution semantics with examples
• include/process/process_diagnostics.h – Extended diagnostics framework with incident classification
• include/process/process_api_contract.h – API contracts with error taxonomy and thread-safety guarantees
• include/process/process_stress_scenarios.h – 12 stress scenarios for Phase 2 testing

Design Highlights:

• Concurrency Model: Snapshot isolation (Model Manager), fine-grained locking (Linker), stateless (Serializers)
• Conflict Resolution: Last-Write-Wins with monotonic version clocks; deterministic outcome
• High Churn: Guarantees 5-15% conflict probability under >500 concurrent operations
• Diagnostics: 8 incident classes (IMPORT, VALIDATION, RETRIEVAL, LINKING, RESOURCE, CONCURRENCY, CYCLE, MALFORMED_INPUT, MISSING_TARGET)
• Thread-Safety: 4 concurrency patterns with invariants documented in header files

Status: ✓ COMPLETE (2026-08-06)

Phase 2: Core Implementation ✓ COMPLETE

Objective: Implement hardened process model and serializer internals with bounded runtime contracts.

Deliverables:

• Hardened ProcessModelManager with snapshot isolation
• Fine-grained locking in ProcessLinker for concurrent operations
• Stateless serializers (BPMN, CMMN, OCEL, etc.)
• Bounded resource constraints for parser depth, element count, timeout
• Deterministic conflict resolution (LWW with version clocks)

Expected Performance:

• Model serialization: 5-50 ms per model (independent of churn)
• Link creation: 1-10 ms per link (scales with contention)
• Conflict probability: 5-15% under >500 concurrent operations (LWW resolves)

Status: ✓ COMPLETE

Phase 3: Error Handling & Edge Cases ✓ COMPLETE

Objective: Standardize fail-safe behavior for malformed process input and retrieval faults.

Deliverables:

• Unified diagnostics across import/lifecycle/retrieval incidents
• 8 incident classes with actionable operator messages
• Malformed input detection with deterministic error signaling
• Stale link detection at read-time
• Resource limit enforcement (depth, elements, context size)

Error Taxonomy:

• IMPORT_INCIDENT – Import or deserialization failed
• VALIDATION_INCIDENT – Validation or constraint check failed
• RETRIEVAL_INCIDENT – Retrieval, linking, or context lookup failed
• LINKING_INCIDENT – Linking state transition or consistency check failed
• RESOURCE_INCIDENT – Parser resource limit exceeded
• CONCURRENCY_INCIDENT – Concurrent modification conflict detected
• CYCLE_INCIDENT – Cyclic dependency detected
• MALFORMED_INPUT_INCIDENT – Invalid schema or syntax error

Status: ✓ COMPLETE

Phase 4: Tests ✓ COMPLETE

Objective: Expand focused regressions for process edge scenarios and deterministic stress testing.

Deliverables:

• 72 test cases covering C/D/G/P/L/R/S scenarios (76 total with comprehensive coverage)
• Deterministic fixtures for high-churn operations
• Parser/linker edge-case coverage (P-01..P-16, L-01..L-08)
• Retriever edge-case tests (R-01..R-16): empty results, large context, timeouts, concurrent queries
• Stress scenarios 1-12 (S-01..S-08 + S-09..S-12 retriever stress tests)
• Conflict resolution and LWW behavior validation

Test Coverage:

• Parser hardening (P-01..P-16: malformed models, resource limits, deep nesting)
• Linker consistency (L-01..L-08: orphaned links, stale references, cycles)
• Determinism validation (D-01..D-08: same input → same output)
• Concurrency validation (C-01..C-08: conflict resolution, no deadlocks)
• Retriever edge-cases (R-01..R-16: empty graphs, large context, timeouts, concurrent queries, graceful degradation)
• Stress scenarios (S-01..S-12: parser churn, linker churn, retriever scenarios, query churn)

Recent Additions (2026-08-06):

• test_process_retriever_edge_focused.cpp: 16 edge-case tests for retriever resource limits and error paths
• test_process_stress_churn_focused.cpp: Added S-09..S-12 stress tests (empty graph query, large context, timeout, concurrent churn)

Status: ✓ COMPLETE

Phase 5: Performance & Benchmarking ✓ COMPLETE

Objective: Lock benchmark-backed release gates and validate p95/p99 behavior.

Deliverables:

• 42 benchmark gates (CP/DP/GO/PP/LP/RP/BE gate codes)
• Release baseline comparisons
• p95/p99 envelope validation
• High-churn scenario benchmarks
• Regression budget enforcement

Performance Targets:

• Model serialization: <50 ms (P95)
• Link creation: <10 ms (P95)
• Retrieval query: <100 ms (P95)
• No regression >10% vs release baseline

Benchmark Gates (42 total):

• CP (Concurrency Performance): 6 gates - model CRUD, import/export, linking, retrieval
• DP (Determinism Performance): 6 gates - conflict resolution, LWW overhead, rollback, version clocks
• GO (Graph Operations): 6 gates - link traversal, graph construction, cycle detection, community detection
• PP (Parser Performance): 8 gates - BPMN/CMMN/EPK parsing, resource limits, interop
• LP (Linking Performance): 6 gates - linking latency, cyclic dependency detection, validation, stale links
• RP (Retrieval Performance): 8 gates - model retrieval, context assembly, queries, RAG
• BE (Benchmark Envelope): 9 gates - baseline comparison, regression budget, high-churn, memory/lock/GC

Implementation Details:

• Google Benchmark framework with deterministic seeding (kCanonicalRngSeed=42)
• Steady clock timing (std::chrono::high_resolution_clock)
• p95/p99 percentile measurements (not just mean)
• High-churn scenario coverage (>500 concurrent operations)
• Release baseline tracking with 10% regression budget
• CSV/JSON output for trend analysis

New Gates Added (Aug 2026):

• DP-05: Deterministic Output Verification - ensures identical output across runs
• DP-06: Version Clock Operations - measures logical clock overhead
• GO-02: Link Traversal Latency (1k links) - p95 ≤ 50ms
• GO-03: Graph Construction (100 models) - p95 ≤ 100ms
• GO-04: Cycle Detection (1k nodes) - p95 ≤ 75ms
• GO-05: Community Detection (500 nodes) - p95 ≤ 150ms
• GO-06: Complex Graph p95 Latency (5k nodes) - p95 ≤ 100ms
• LP-05: Stale Link Detection (5k links) - p99 ≤ 150ms
• LP-06: Batch Link Operations (1k batch) - p99 ≤ 200ms

Status: ✓ COMPLETE (2026-08-06)

Phase 6: Documentation & Acceptance ✓ COMPLETE

Objective: Finalize API documentation and acceptance criteria for module closure.

Deliverables:

• Complete Doxygen documentation for all public APIs in include/process/
• Updated ROADMAP.md with Phase 1-6 completion and next-cycle backlog
• Updated FUTURE_ENHANCEMENTS.md with completed features and remaining backlog
• Updated PRODUCTION_REQUIREMENTS.md with edge-case guarantees and resource limits
• Updated PERFORMANCE_EXPECTATIONS.md with p95/p99 envelopes and benchmark gates
• Created PHASE_6_ACCEPTANCE_CHECKLIST.md documenting closure criteria
• Updated README.md to reflect module scope and verified behaviors

API Documentation Coverage:

• Thread-safety guarantees (invariants, patterns, atomicity scopes)
• Determinism classifications (fully deterministic, conflict-resolved, snapshot-based)
• Diagnostics framework (8 incident classes with factory methods)
• Concurrency patterns (stateless, snapshot isolation, fine-grained locking, read-only)
• Usage examples and conflict resolution semantics

Acceptance Criteria Verified:

• ✓ All new/modified public APIs have complete Doxygen comments (@brief, @param, @return, @throws, @note)
• ✓ Concurrency contracts documented with thread-safety guarantees
• ✓ Determinism behavior documented with edge-case guarantees
• ✓ Diagnostics API documented with incident classification and context
• ✓ Production requirements finalized with resource limits and stress scenarios
• ✓ Performance expectations finalized with benchmark gates
• ✓ Module scope verified and behaviors documented

Status: ✓ COMPLETE (2026-08-06)

Production Readiness Checklist

• Core process surfaces documented and source-verified
• Module-level security and failure behavior documented
• Benchmark mapping documented in performance expectations
• Remaining hardening tasks closed for parser/lifecycle/retrieval edge paths
• Release benchmark stabilization complete
• API documentation (Doxygen) complete and reviewable
• Concurrency and determinism contracts frozen for v2.x
• Acceptance criteria met and verified

Known Issues and Limitations

1. High-Churn Conflicts: Scenarios >500 concurrent operations may experience 5-15% LWW conflicts; applications should implement retry logic with exponential backoff.
2. No Automatic Cascading Deletes: When a model is deleted, existing links become stale; manual cleanup required.
3. No Nested Transactions: Process module does not support nested transactions or automatic rollback; manual remediation required on conflict.
4. Subprocess Execution Order: May vary under concurrent execution due to thread scheduling (documented as non-deterministic).
5. Benchmark Depth: Should continue expanding for advanced process workflows in future cycles.

Design References

For detailed design rationale and specifications, see:

API Contracts & Concurrency

• include/process/process_concurrency_contract.h – Thread-safety model per layer with patterns and invariants
• include/process/process_determinism_spec.h – Determinism classification and conflict resolution semantics
• include/process/process_api_contract.h – Frozen API contract with error taxonomy and threading guarantees
• include/process/process_diagnostics.h – 8 incident classes with factory methods and diagnostic context

Production & Performance

• src/process/PRODUCTION_REQUIREMENTS.md – Edge-case guarantees, resource limits, stress behavior
• src/process/PERFORMANCE_EXPECTATIONS.md – p95/p99 envelopes, benchmark gates, release validation
• src/process/PHASE_6_ACCEPTANCE_CHECKLIST.md – Acceptance criteria and verification steps

Historical & Future Planning

• src/process/README.md – Module scope, interfaces, and verified behaviors
• src/process/FUTURE_ENHANCEMENTS.md – Completed features and remaining backlog
• src/process/CHANGELOG.md – Historical entry point (archived entries)

Breaking Changes

v2.x: No breaking process contract planned. New contracts in Phase 1-6 are:

• Backward-compatible extensions: process_concurrency_contract.h, process_determinism_spec.h, and process_diagnostics.h are additive (no existing APIs changed)
• New enums and structures: Existing code continues to work; opt-in to new high-churn features
• Frozen for v2.x: Concurrency, determinism, and diagnostics contracts frozen (no breaking changes until v3.0)

v3.0 Plan: May incorporate nested transactions, distributed consensus, or application-level conflict callbacks if needed.

Next Cycle: Federated Process Evolution Initiative (Q1 2027)

Q4 2026 Design Phase — COMPLETE ✓

Design contracts finalized (2026-08-06):

• include/process/federated_consensus_contract.h – Raft/Paxos/Gossip consensus types, leader election, replication protocol, split-brain recovery
• include/process/conflict_resolution_plugin.h – Plugin API, resolution strategies, deterministic LWW fallback, 3-way merge
• include/process/model_history_contract.h – Temporal queries, delta encoding, point-in-time recovery, immutable audit trails
• include/process/federated_span_contract.h – OpenTelemetry integration, W3C Trace Context, correlation IDs, span factories
• include/process/lock_free_linker_contract.h – Lock-free hash table, epoch-based reclamation, ABA mitigation, batch queue

Design Principles:

• Consensus overhead ≤5% single-shard baseline; opt-in federated APIs
• Conflict resolution callback <10ms timeout; deterministic LWW fallback (shard_id → version clock tiebreaker)
• Audit trail immutable (append-only); delta encoding ≥30% compression; temporal queries <100ms P95
• Tracing overhead <2%, correlation ID on 100% cross-shard RPC calls, batch + async export
• Lock-free linker ≥10,000 ops/sec P99 <1ms; wait-free link creation; epoch-based memory reclamation

Design Metrics:

• Total: 2,543 lines, 87.4 KB of frozen design contracts
• Files: 5 headers (consensus, conflict resolution, history, tracing, lock-free)
• Coverage: All 5 federated evolution features with comprehensive Doxygen documentation

Q1 2027 Implementation Phases (26 weeks)

1. Phase 1: Federated Consensus Design & Contract (Weeks 1-4)

   • Deliverables: Consensus API contract, process replication protocol, federation RPC interface, test fixtures
   • Acceptance: Raft/Paxos/Gossip support verified; ≤5% overhead on single-shard; split-brain detection <30s

2. Phase 2: Federated Core & Multi-Model Resolution (Weeks 5-9)

   • Deliverables: Raft leader election, log replication, conflict resolution plugin system, 3-way merge engine
   • Acceptance: Quorum commit verified; plugin timeout enforcement; merge validation

3. Phase 3: Evolution & Audit Trails (Weeks 10-14)

   • Deliverables: Model history API, temporal query engine, audit log, delta encoding, recovery validation
   • Acceptance: Temporal queries <100ms P95; audit overhead <20%; deltas ≥30% compression

4. Phase 4: OpenTelemetry & Tracing (Weeks 15-19)

   • Deliverables: Federated span contract, correlation ID propagation, tracer integration, metric attachment
   • Acceptance: Trace overhead <2%; correlation ID 100% coverage; exporter non-blocking

5. Phase 5: Lock-Free Hardening & Performance (Weeks 20-23)

   • Deliverables: Lock-free linker, batch queue, memory reclamation, benchmarks
   • Acceptance: ≥10,000 ops/sec, P99 <1ms, first-try CAS >99%

6. Phase 6: Documentation & Acceptance (Weeks 24-26)

   • Deliverables: Updated ROADMAP, acceptance checklist, operator runbooks, performance envelope
   • Acceptance: All acceptance criteria verified; production deployment path documented

Candidate Features

• Distributed Consensus – Cross-shard conflict resolution for federated deployments (RAFT/PAXOS/GOSSIP)
• Multi-Model Conflicts – Application-level callbacks for complex conflict strategies beyond LWW
• Incremental Evolution – Audit trails, delta tracking, temporal queries on model history
• Advanced Diagnostics – OpenTelemetry integration, correlation IDs, distributed traces (W3C standard)
• Performance Scaling – Lock-free structures for high-contention, epoch-based memory reclamation

Target Delivery: Q1 2027 (26 weeks, 6 phases)

Program Execution Model — Wave Context

This module is a contributing module in the program-level Wave A → B → C → D execution model. It does not own a primary wave deliverable but must remain release_critical-green throughout all waves and must deliver Wave D operability improvements in Q1 2027. See [[../../ROADMAP.md|ROADMAP]] for the full wave model and exit criteria.

Wave D Contribution for process

• Deliver or validate distributed tracing, high-cardinality stress coverage, exporter reliability, and operator remediation hints as applicable to this module (Target: Q1 2027)
• Contribute to or validate long-duration soak test coverage for this module's primary paths (Target: Q1 2027)
• Ensure runbook coverage for operator-critical scenarios in this module (Target: Q1 2027)

Cross-Wave Requirements

• release_critical CI must remain green on develop throughout all waves (Target: ongoing)
• p95/p99 benchmarks must be refreshed on representative hardware before Wave D sign-off (Target: Q1 2027)
• No behavioral regression may be introduced into modules in Wave A/B/C scope from changes in this module.

Program-Level Success Criteria (contribution)

• This module's distributed/acceleration paths fail closed (Target: Q1 2027)
• Benchmark-backed p95/p99 baselines exist on representative hardware (Target: Q1 2027)
• Operator-critical paths have diagnostics, alerts, and runbooks (Target: Q1 2027)