3cfaa1e1d3
Phase 1 delivers the complete durability and storage layer:
- WAL with crash recovery: Append-only journal with BLAKE3 checksums,
fsync guarantees, and proper seek-to-EOF on reopen
- Storage engine: sled-backed KVStore with scan_prefix for range queries
- Content-addressed storage: H:{hash}, V:{hash}, E:{hash} key patterns
- Ingestor: Background worker tailing WAL, writing to KV with 8-byte
aligned record headers for rkyv zero-copy deserialization
- Comprehensive tests: 31 tests covering crash recovery, round-trips,
and multi-cycle durability
New crates: stemedb-wal, stemedb-storage, stemedb-ingest
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
66 lines
3.4 KiB
Markdown
66 lines
3.4 KiB
Markdown
# StemeDB (Episteme) Project Context
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## Project Overview
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**StemeDB (Episteme)** is a probabilistic, log-structured, content-addressed knowledge graph database designed as the "Cortex" for autonomous AI research agents. Unlike traditional databases that enforce a single mutable state, StemeDB preserves immutable history and resolves conflicting assertions at read-time using "Lenses."
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It serves as the "Git for Truth," allowing agents to:
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* **Assert** facts with cryptographic signatures and confidence scores.
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* **Vote** on assertions to build consensus without lock contention.
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* **Fork** reality to simulate "what-if" scenarios (Overlay Graphs).
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* **Resolve** truth dynamically via lenses like Consensus, Authority, or Recency.
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## Tech Stack
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* **Language:** Rust (2024 edition)
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* **Durability:** `stemedb-wal` (Quarantine Pattern with `fs2`, `blake3` checksums)
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* **Storage:** `stemedb-storage` (`sled` embedded KV, abstracted via `KVStore` trait)
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* **Serialization:** `rkyv` (Zero-copy deserialization for high performance)
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* **Ingestion:** `stemedb-ingest` (Async background worker bridging WAL and Store)
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* **Simulation:** `stemedb-sim` (Agent-based modeling to verify system behavior)
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## Architecture
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The system follows a "Spine -> Lattice -> Cortex" architecture:
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1. **The Spine (Durability):**
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* **Write-Ahead Log (WAL):** Append-only log with strict `fsync` guarantees.
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* **Ingestor:** Background task that tails the WAL and indexes data.
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* **KV Store:** Persistent storage for assertions and indexes.
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2. **The Lattice (Connectivity) - *In Progress*:**
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* **Ballot Box:** High-velocity vote stream.
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* **Materialized Views:** Pre-computed truth states.
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3. **The Cortex (Reasoning) - *Planned*:**
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* **Lenses:** WASM-based filters for truth resolution.
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* **SMT:** Sparse Merkle Trees for efficient branching.
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## Key Files & Directories
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* `stemedb/`
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* `crates/`
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* `stemedb-core/`: Core data structures (`Assertion`, `Vote`, `Epoch`) and types.
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* `stemedb-wal/`: Durability primitives (`Journal`, `FsyncGuard`, `Record`).
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* `stemedb-storage/`: Storage engine abstraction and `sled` implementation.
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* `stemedb-ingest/`: Async ingestion pipeline logic.
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* `stemedb-sim/`: "The Arena" simulation for end-to-end verification.
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* `architecture.md`: Detailed system design and data flow.
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* `roadmap.md`: Phased implementation plan and status.
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* `usage.md`: Rust API usage guide and vision for agent interaction.
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* `Makefile`: Build and quality automation.
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## Building and Running
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The project uses a `Makefile` for common tasks:
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* **Build:** `make build` (Compiles the workspace)
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* **Test:** `make test` (Runs unit tests across all crates)
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* **Quality Check:** `make quality` (Runs fmt, strict clippy linting, duplication checks, and tests)
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* **Run Simulation:** `cargo run -p stemedb-sim` (Executes the spine verification simulation)
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* **Format:** `make fmt` (Auto-formats code)
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## Development Conventions
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* **Strict Quality:** `make quality` must pass before committing.
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* No `unwrap()` or `expect()` in production code (enforced by clippy).
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* Zero warnings allowed.
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* Missing documentation is a hard error.
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* **Testing:** Every crate must have unit tests. The `stemedb-sim` crate serves as the integration test suite.
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* **Architecture:** Follow the "Defensive by Default" philosophy. Durability > Speed > Features.
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