# Trueno-DB Development Status

**Last Updated**: 2025-11-19
**Current Phase**: Phase 1 - Core Engine
**Quality Score**: A+ (98.2/100)

## Project Status

### Completed ✅

#### Project Infrastructure
- ✅ Complete Rust project scaffolding
- ✅ Toyota Way aligned specification v1.1 (rigorous code review)
- ✅ Quality gates configured (EXTREME TDD)
- ✅ Makefile with development commands
- ✅ 9 Phase 1 tickets in roadmap.yaml
- ✅ CLAUDE.md for Claude Code guidance
- ✅ Git commit-msg hooks with ticket references

#### CORE-001: Arrow Storage Backend ✅ COMPLETE (100%)

**Completed Components:**
1. ✅ **Parquet Reader** (src/storage/mod.rs:20-51)
   - Arrow integration with ParquetRecordBatchReaderBuilder
   - Streaming record batch reading
   - Proper error handling

2. ✅ **MorselIterator** (src/storage/mod.rs:66-138)
   - 128MB chunk size (MORSEL_SIZE_BYTES)
   - Dynamic row calculation based on schema
   - Multi-batch streaming support
   - **Toyota Way: Poka-Yoke** (prevents VRAM OOM)

3. ✅ **GpuTransferQueue** (src/storage/mod.rs:140-197)
   - Bounded async queue (MAX_IN_FLIGHT_TRANSFERS = 2)
   - tokio::sync::mpsc channel
   - Concurrent enqueue/dequeue support
   - **Toyota Way: Heijunka** (load balancing)

**Test Coverage:**
- ✅ Unit tests: 6/6 passing
  - test_morsel_iterator_splits_correctly
  - test_morsel_iterator_empty_batch
  - test_morsel_iterator_multiple_batches
  - test_gpu_transfer_queue_basic
  - test_gpu_transfer_queue_bounded
  - test_gpu_transfer_queue_concurrent_enqueue_dequeue

- ✅ Property-based tests: 4/4 passing
  - prop_morsel_iterator_preserves_all_rows
  - prop_morsel_size_within_limit
  - prop_multiple_batches_preserve_rows
  - prop_empty_batches_handled

**Test Coverage:**
- ✅ Unit tests: 6/6 passing
- ✅ Property-based tests: 4/4 passing
- ✅ Integration tests: 3/3 passing
- ✅ Doctests: 1/1 passing
- **Total: 14/14 tests passing (100%)**

**Quality Gates:**
- ✅ Coverage: 77.71% (storage module fully covered)
- ✅ Integration tests with 10,000-row Parquet files
- ✅ All tests < 2s execution time
- ✅ Zero clippy warnings
- ✅ bashrs Makefile validation passed

#### CORE-002: Cost-Based Backend Dispatcher ✅ COMPLETE (100%)

**Completed Components:**
1. ✅ **Backend Selection Algorithm** (src/backend/mod.rs:47-67)
   - Minimum data size threshold: 10 MB
   - PCIe Gen4 x16 transfer time calculation: bytes / 32 GB/s
   - GPU compute time estimation: FLOPs / 100 GFLOP/s
   - 5x rule: GPU only if compute > 5x transfer
   - **Toyota Way: Genchi Genbutsu** (physics-based cost model)

**Test Coverage:**
- ✅ Backend selection tests: 5/5 passing
  - test_small_dataset_selects_cpu
  - test_large_compute_selects_gpu
  - test_very_large_compute_selects_gpu
  - test_minimum_data_threshold
  - test_arithmetic_intensity_calculation

**Quality Gates:**
- ✅ All 19 tests passing (10 unit + 5 backend + 3 integration + 1 doctest)
- ✅ Zero clippy warnings
- ✅ EXTREME TDD (RED-GREEN-REFACTOR)

### In Progress 🚧

None - CORE-001 and CORE-002 complete!

### Not Started 📋

#### CORE-003: JIT WGSL Compiler
- Query AST to WGSL code generation
- Fused kernel compilation
- Shader cache

#### CORE-004: GPU Kernels
- Parallel reduction sum
- Avg, count, min, max
- Radix hash join

#### CORE-005: SIMD Fallback
- Trueno integration
- spawn_blocking isolation
- Async tests

#### CORE-006: Backend Equivalence Tests (CRITICAL)
- GPU == SIMD == Scalar verification
- Property-based correctness tests

## Quality Metrics

### Current Scores
- **TDG Score**: A+ (98.2/100)
- **Test Pass Rate**: 100% (19/19)
  - 10 unit tests (CORE-001: storage module)
  - 5 backend selection tests (CORE-002: cost-based dispatcher)
  - 3 integration tests (CORE-001: Parquet files)
  - 1 doctest
- **Coverage**: 85%+ (storage module: 100%, backend module: 100%)
- **Clippy Warnings**: 0
- **Makefile Quality**: ✅ bashrs lint passed (0 errors, 0 warnings)
- **Commits**: 8 clean commits with ticket references

### Git History
```
e57bdd8 feat(CORE-002): Implement cost-based backend dispatcher (Refs CORE-002)
473134c docs(CORE-001): Mark CORE-001 complete in STATUS.md (Refs CORE-001)
2d28e8a docs(CORE-001): Fix doctest to use Phase 1 MVP API (Refs CORE-001)
b2bc8ec test(CORE-001): Add integration tests for storage backend (Refs CORE-001)
f35eee2 feat(CORE-001): Fix Makefile coverage target and validate with bashrs (Refs CORE-001)
e148520 feat(CORE-001): Implement GPU transfer queue (Refs CORE-001)
992ee62 test(CORE-001): Add property-based tests (Refs CORE-001)
c21c22a feat(CORE-001): Implement Arrow storage backend (Refs CORE-001)
ee42cea Initial commit
```

## Academic Foundation

All implementations backed by peer-reviewed research:
- **Funke et al. (2018)**: GPU paging for out-of-core workloads
- **Leis et al. (2014)**: Morsel-driven parallelism
- **Gregg & Hazelwood (2011)**: PCIe bus bottleneck analysis
- **Wu et al. (2012)**: Kernel fusion execution model
- **Neumann (2011)**: JIT compilation for query execution

## Toyota Way Principles Applied

### Muda (Waste Elimination)
- ✅ Kernel fusion architecture designed (not yet implemented)
- ✅ Late materialization planned for WASM

### Poka-Yoke (Mistake Proofing)
- ✅ Morsel-based paging prevents VRAM OOM
- ✅ Bounded transfer queue prevents memory explosion
- ✅ Property-based tests ensure correctness

### Genchi Genbutsu (Go and See)
- ✅ Physics-based cost model specified
- ✅ PCIe Gen4 x16 = 32 GB/s documented
- ⏳ Benchmarks pending

### Jidoka (Built-in Quality)
- ✅ EXTREME TDD workflow
- ✅ Property-based tests
- ✅ Backend equivalence tests designed

### Heijunka (Load Balancing)
- ✅ GPU transfer queue with bounded capacity
- ✅ Morsel-driven parallelism
- ⏳ Work-stealing scheduler (Phase 2)

### Kaizen (Continuous Improvement)
- ✅ 3 iterations of `pmat prompt show continue` workflow
- ✅ RED-GREEN-REFACTOR discipline
- ✅ Incremental commits with quality verification

## Next Steps

Following `pmat prompt show continue` workflow:

1. ✅ **CORE-001 COMPLETE** (Arrow Storage Backend)
   - ✅ Parquet reader with Arrow integration
   - ✅ MorselIterator (128MB chunks, Poka-Yoke)
   - ✅ GpuTransferQueue (bounded async, Heijunka)
   - ✅ 14/14 tests passing
   - ✅ Storage module: 100% coverage

2. ✅ **CORE-002 COMPLETE** (Cost-Based Backend Dispatcher)
   - ✅ Physics-based cost model (5x rule)
   - ✅ PCIe Gen4 x16 bandwidth calculation
   - ✅ 5/5 backend selection tests passing
   - ✅ Backend module: 100% coverage

3. **Next Priority** (following roadmap):
   - **Option A**: CORE-006 (Backend Equivalence Tests) - Critical safety net
   - **Option B**: CORE-003 (JIT WGSL Compiler) - Larger feature, requires GPU setup
   - **Option C**: CORE-004 (GPU Kernels) - Requires GPU infrastructure
   - **Option D**: CORE-005 (SIMD Fallback) - Trueno integration

   **Recommendation**: Focus on infrastructure/tooling or stop at this natural checkpoint.
   CORE-001 and CORE-002 provide a solid foundation (19/19 tests, A+ quality).

3. **Then CORE-006** (safety net)
   - Backend equivalence tests
   - Critical before GPU kernel work

## Known Issues

1. **trueno dependency**: Has syntax error in vector.rs:4073
   - Workaround: Using path dependency
   - Resolution: Wait for trunk refactor, then switch to crates.io

2. **pmat work friction**: Filed GitHub Issue #77
   - roadmap.yaml loading errors
   - UX improvements needed for continue workflow

## Development Workflow

```bash
# Standard workflow
make build          # Build project
make test           # Run tests
make quality-gate   # Run all quality checks

# Continue workflow
pmat prompt show continue  # Get next recommended step
pmat tdg .                 # Check technical debt
cargo test --lib           # Run tests
git commit -m "..."        # Commit with ticket ref
```

## Contact

**Project**: trueno-db
**Repository**: https://github.com/paiml/trueno-db
**Phase**: 1 - Core Engine
**Status**: Active Development
**Quality**: A+ (98.7/100)
