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Why Rust? — The Rewrite Story

CodeGraph is a from-scratch Rust rewrite of the previous TypeScript implementation.

The Old Stack (TypeScript)

Component Technology Pain Points
Runtime Node.js (embedded) ~50 MB baseline, multi-second cold start
Parsing 20+ tree-sitter WASM grammars WASM overhead, no parallel parsing
Storage Native SQLite addon (better-sqlite3) Node-gyp builds, platform issues
Distribution Single binary via pkg ~140 MB, not truly static

Result: ~140 MB binary, 2–3 second startup, complex build pipeline.

The Rust Rewrite

What Changed

Before (TS) After (Rust) Impact
Node runtime None — static binary -80 MB, sub-ms startup
WASM grammars Statically-linked tree-sitter C Native speed, rayon parallelism
Native SQLite addon Bundled rusqlite (bundled feature) No system deps, no node-gyp
pkg bundler cargo build --release + strip Standard Rust toolchain

Build Optimizations

# Cargo.toml (workspace)
[profile.release]
lto = "fat"           # Cross-crate optimization
codegen-units = 1     # Maximum optimization
strip = true          # Strip symbols
panic = "abort"       # Smaller binary, no unwinding

Results

Metric TypeScript Rust Improvement
Binary size ~140 MB ~58 MB 2.4× smaller
Cold start ~2–3 s <100 ms 20–30× faster
Indexing (139 files) ~1 s ~190 ms ~5× faster
Memory (idle) ~80 MB ~15 MB 5× less
Dependencies 500+ npm packages ~100 crates Simpler supply chain

Why These Choices?

tree-sitter (C) over WASM

  • Parallel parsing: rayon thread pool across files — WASM can't do true parallelism
  • Zero-copy: Parse trees reference source bytes directly
  • No WASM overhead: Function calls, memory copies eliminated
  • Grammar updates: tree-sitter C libs updated independently

rusqlite (bundled SQLite) over native addon

  • Pure Rust + bundled C: rusqlite with bundled feature compiles SQLite from source
  • No system SQLite needed: Works on minimal containers (distroless, scratch)
  • WAL mode: Concurrent readers during write
  • No node-gyp: Eliminates entire class of build failures

Single Binary Philosophy

codegraph binary contains:
  ├── tree-sitter parsers (14 languages, statically linked)
  ├── SQLite (bundled, WAL mode)
  ├── LMDB (bundled via lmdb-rkv)
  ├── Redis client (async, tokio)
  ├── Postgres/MySQL drivers (sqlx, compiled in)
  ├── ONNX Runtime + fastembed (BGE-small model loader)
  └── MCP server (rmcp SDK)

No:

  • External processes
  • Shared libraries (except libc)
  • Runtime downloads (model cached separately)
  • Daemon/background service

Trade-offs

Gain Cost
Fast startup Longer compile time (~3–5 min clean)
Small binary Larger binary than minimal CLI (~58 MB)
Parallel parsing More complex build (C dependencies)
No runtime deps Can't hot-reload grammars (rebuild needed)
Type safety Learning curve for contributors

Verification

# Build release
cargo build --release -p codegraph

# Check size
ls -lh target/release/codegraph
# ~58 MB

# Verify static linking
ldd target/release/codegraph
# Should show only libc, libdl, libpthread, libm, libgcc_s

# Benchmark startup
time target/release/codegraph --version
# <100 ms

# Benchmark indexing
cd /path/to/project
time target/release/codegraph init
# ~190 ms for ~139 files

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