moeix 0.5.1

Sub-millisecond code search via sparse trigram indexing.
Documentation
moeix-0.5.1 has been yanked.

ix

crates.io docs.rs License: MIT CI

Sub-millisecond code search via sparse trigram indexing.

ix pre-computes a byte-level trigram index to narrow search candidates to a fraction of the total file set, then verifies matches with a memory-constant streaming architecture. This eliminates the linear-scan bottleneck that slows grep and ripgrep on large codebases.

Install

cargo install moeix

This installs two binaries:

  • ix — CLI search tool
  • ixd — background daemon for continuous indexing (requires notify feature, enabled by default)

Quick Start

# Index a directory
ix --build /path/to/repo

# Search
ix "fn validate"

# Search with regex
ix --regex "fn\s+\w+_handler"

# Search with context lines
ix --context 3 "TODO"

# Negation filter (exclude matches)
ix "error" --negate "test"

# Show query statistics
ix --stats "struct Config"

How It Works

  1. Index — ix --build walks the directory, extracts byte-level trigrams from every file, and writes a compressed index to .ix/shard.ix.
  2. Plan — On search, the query is decomposed into trigrams. The index is consulted to find candidate files that contain all required trigrams.
  3. Verify — Candidates are streamed through a regex matcher with constant memory usage, producing precise line-level results.

Index Format (v1.3)

All integers are little-endian, all offsets absolute from file start, 8-byte aligned sections.

Section Description
Header 256 bytes: magic IX01, version, flags, section offsets
File table Per-file metadata: path hash, content hash, size, posting offset
Trigram table (CDX) Delta-encoded + varint + ZSTD compressed in 1024-entry blocks
Block index (u32 first_key, u64 block_offset) × N + sentinel
Posting lists Per-trigram file IDs, delta-encoded + varint + ZSTD
String pool Interned file paths

CDX compression is always-on since v1.3. The reader does a two-level search: block index → decompress block → linear scan.

Not backward compatible with v1.1 or v1.2. Rebuild indexes after upgrading:

rm -rf .ix/
ix --build .

Daemon

ixd watches a directory for file changes and incrementally updates the index:

ixd /path/to/repo

The daemon exposes a Unix domain socket for external consumers (editors, tooling):

$XDG_RUNTIME_DIR/ixd/{hash}.sock

Protocol is NDJSON — one JSON object per newline-terminated line. Push notifications for file changes and status updates; query/response for history and status queries.

ix CLI does not use the socket — it reads the index file directly.

Performance

Metric Value
Index ratio ~4× source size (ZSTD level 3)
Selective query (10% match) 40ms — scans 10× fewer files than ripgrep
Small dataset (all match) 305ms — ripgrep wins on small/all-match workloads
Cold start <3s
Hot path p99 <50ms

ix wins when the trigram index can eliminate most files from scanning. On small repos or queries where every file matches, linear-scan tools like ripgrep are faster.

Feature Flags

Flag Default Description
notify yes File watcher + daemon (ixd)
decompress no gz/zst/bz2/xz decompression
archive no zip/tar archive support
full no All optional features

Library

ix is also a library (moeix on crates.io, ix as the crate name):

[dependencies]
moeix = "0.5"

use ix::{Reader, Executor};

let reader = Reader::open(".ix/shard.ix")?;
let mut executor = Executor::new(&reader);
let matches = executor.execute(/* query */);

See docs.rs/moeix for full API documentation.

Building

cargo build --all-features
cargo test --all-features
cargo clippy --all-features -- -D warnings

Requires Rust 1.85+.

License

MIT