---
name: Session 2026-04-13/14 — Storage layer trial and SQLite+LanceDB migration
description: Benchmarked three storage backends (NFCorpus/BEIR), chose SQLite+LanceDB,
  migrated all 13 modules. 40 infrastructure errors remain.
type: project
originSessionId: e02702fe-d3d4-4b0d-a71b-d83a06479fe2
permalink: claude-memory/session-2026-04-13-storage-trial
---

## What we did

### Storage Layer Trial (2026-04-13)
- Designed and executed three-branch evaluation of SurrealDB alternatives
- **Branch A** (`trial/storage-surrealdb-only`): SurrealDB control
- **Branch B** (`trial/storage-sqlite-lance`): better-sqlite3 + LanceDB — SELECTED
- **Branch C** (`trial/storage-sqlite-pure`): better-sqlite3 + FTS5 + sqlite-vec
- Built shared benchmark harness with NFCorpus (BEIR) dataset, real mxbai-embed-large embeddings (1024-dim), official relevance judgments
- Benchmark metrics: NDCG@10, recall@10 vs brute-force, ingest throughput, memory ceiling, cold start, read-under-write P95

### Benchmark Results
| Metric | SurrealDB | SQLite+Lance | SQLite-Pure |
|--------|:---------:|:------------:|:-----------:|
| Ingest (docs/min) | 4,441 | 8,079 | 173,207 |
| Hybrid NDCG@10 | 0.000 | **0.433** | 0.421 |
| Vector recall@10 | 0.000 | **0.984** | 0.984 |
| FTS NDCG@10 | 0.000 | **0.375** | 0.195 |
| RSS (MB) | 164 | 228 | 129 |

### Migration (2026-04-13 evening → 2026-04-14 early morning)
- Built core storage layer: `src/core/storage/sqlite-lance.ts` (getSqliteDb, getLanceDb, migrations, circuit breakers)
- Created SQLite/LanceDB implementations for all 13 modules (8,517 lines total)
- Created compatibility bridges: each module's `storage.ts` re-exports SQLite functions under original names
- Wired all module `index.ts` files to use `getSqliteDb()` + `initXStorage()`
- Changed all module pipeline/query files from `SurrealQueryBuilder` to `StorageDb = SqliteHandle`
- Converted inline SurrealQL in entity/pipeline.ts (resolution candidates, fuzzy match → SQLite + app-level Levenshtein)
- Rewrote training/model-registry.ts for SQLite
- Stubbed entity/temporal reconciliation (repair-only, not hot path)

### wshobson/agents installed
- 41 agents + 40 skills installed from https://github.com/wshobson/agents to match Seb's setup
- Installed at `~/.claude/agents/` (namespaced: `plugin-agent.md`)
- Skills at `~/.claude/skills/`

## What we decided

### Branch B (SQLite + LanceDB) chosen because:
1. **Recall quality is primary** — memory system must find what it stored. Tantivy FTS (0.375 NDCG) > FTS5 (0.195)
2. **Scale-ready** — LanceDB HNSW is O(log n), sqlite-vec brute-force is O(n). BMF is designed to grow
3. **Each tool does its job** — better-sqlite3 (25 yrs, trillions of deployments) for relational; LanceDB (Rust, Arrow, Tantivy) for vectors+FTS
4. David's instinct about dual-stack was right — the "single stack" burn was about *maturity*, not *count*

### StorageDb = SqliteHandle (not `any` or `unknown`)
David explicitly rejected `any` as a type escape hatch. The prime directive applies: "Do things once, correctly." Using `StorageDb = SqliteHandle` gives proper type safety through the bridge layer.

### Bridge pattern chosen over full signature rewrite
Instead of changing 86+ files' function signatures, bridge `storage.ts` files re-export SQLite functions under original names. Pipeline/query files change only their type import. This minimizes blast radius while maintaining type safety.

## What's unresolved

### 40 compile errors in infrastructure layer
All in non-module files. Module layer is clean (zero errors).

Files with errors:
- `bootstrap.ts` (15 errors) — inline SurrealQL for circle wiring, telemetry, invite codes, budget seeding, meld bootstrap
- `orchestrator.ts` (8 errors) — cursor store, snapshot queries, IntLiteral usage
- MCP tools/resources (10 errors) — budget resources, knowledge tools, training-pairs
- Knowledge services (4 errors) — circle-recall, clasp-knowledge, interaction-service, signal-receiver
- Inference/perception (3 errors) — teacher-enrichment, similarity-probe

These files have inline SurrealQL (`db.execute(db.query\`...\`)`) that needs converting to SQLite SQL, same pattern as entity/pipeline.ts.

### Factory, Meld, and Inference layers not yet touched
- `src/factory/` — factory.ts, checkpoint.ts, dedup.ts, job-store.ts, migrations.ts all use `getSurrealDB` and SurrealQL
- `src/meld/` — catalog.ts, bootstrap.ts, pulse.ts, discovery.ts, health.ts, identity.ts, slugs.ts, threats.ts, storage.ts, services/
- `src/inference/` — graduation-storage.ts, teacher-enrichment-storage.ts
- `src/core/reasonchain/` — indexes.ts
- `src/core/lifecycle/` — operations.ts, retrieval-tracker.ts
- `src/core/keystone/` — telemetry-schema.ts, readiness/cursor-store.ts, readiness/replay-coordinator.ts, readiness/resource-monitor.ts

### Reconciliation functions stubbed
- `entity/reconciliation.ts` — reconcileEntityMentionCounts, reconcileCoOccurrenceEdges → return empty results
- `temporal/reconciliation.ts` — reconcileCausalChainConfidence, reconcileTemporalCoverage → return empty results
These run during `ctl repair` only. Need reimplementation before repair is usable.

### SurrealDB not yet removed
- Dependencies `surrealdb` and `@surrealdb/node` still in package.json
- `src/core/storage/surrealdb.ts` (1,099 lines) still present
- `storage-surreal.ts` backup files in every module
- Tests still import from surrealdb.ts

## Next actions (ordered)

1. **Convert remaining 40 infrastructure errors** — bootstrap.ts, orchestrator.ts, MCP tools, knowledge services. Same bridge pattern: create storage functions, remove inline SurrealQL
2. **Wire factory layer** — factory.ts, checkpoint.ts, dedup.ts, job-store.ts need SQLite storage bridges
3. **Run tests** — `npm test` to find test failures (tests use `mem://` SurrealDB, need SQLite `:memory:` equivalent)
4. **End-to-end test** — start BMF with `BM_STORAGE_BACKEND=sqlite-lance`, observe/recall roundtrip
5. **Run NFCorpus benchmark on wired system** — verify recall quality matches benchmark adapter results
6. **Reimplement reconciliation** — entity/temporal reconciliation for `ctl repair`
7. **Deprecate SurrealDB** — remove deps, surrealdb.ts, storage-surreal.ts backups

## Key files

| File | Status | Purpose |
|------|--------|---------|
| `src/core/storage/sqlite-lance.ts` | DONE | Core connection management |
| `src/modules/*/storage-sqlite.ts` | DONE | SQLite implementations (13 files, 8.5K lines) |
| `src/modules/vector/storage-lance.ts` | DONE | LanceDB vector+FTS implementation |
| `src/modules/*/storage.ts` | DONE | Bridge files (delegate to SQLite) |
| `src/modules/*/storage-surreal.ts` | PRESERVED | SurrealDB backups |
| `benchmarks/` | DONE | NFCorpus harness, 3 adapters, dataset generator |
| `docs/thinking/David/l1-reliability/2026-04-13-storage-layer-trial.md` | DONE | Decision document |

## Branch state
- `trial/storage-sqlite-lance` — 17 commits ahead of main, all pushed
- `trial/storage-surrealdb-only` — control branch (unchanged)
- `trial/storage-sqlite-pure` — comparison branch (unchanged)
- `trial/storage-common` — shared benchmark harness