Horreum ⚡

Ultra-fast, zero-allocation, authenticated in-memory & persistent cache service written in pure Go.

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Overview

Horreum is a high-performance distributed key-value caching system designed with a strict zero-allocation hot-path architecture. Powered by custom memory-mapped arena allocators, S3-FIFO eviction queues, pure-Go LZ4 compression, and authenticated AES-256-GCM encryption at rest, Horreum achieves microsecond latency with zero garbage collection overhead on value storage.

Key Features

• Zero-Allocation Hot Path: Custom mmap arena allocator (internal/arena) operating on unsafe.Slice handles. No heap GC pressure on value mutations.
• S3-FIFO Eviction: Lock-free touch operations via atomic frequency counters and dual ring-buffer queues (Small & Main) outperforming classic LRU.
• Dual Transport Layer:
  • TCP: Connection-pinning router hashing (remoteIP + localPort) to shard workers.
  • QUIC: Native TLS 1.3 multiplexed stream support using quic-go.
• Pure-Go LZ4 Compression: Optional fast value compression with pooled buffer recycling achieving ~2 GB/s decompress throughput.
• Authenticated Encryption at Rest: AES-256-GCM AEAD encryption with automated 32-byte key generation (~4.9 GB/s decrypt throughput via AES-NI).
• Stdlib-Only YAML Config: Zero-dependency YAML configuration parser supporting binary unit sizes (256MiB, 1GiB).
• Low-Overhead Logging: log/slog structured logging with token-bucket rate-limiting on network errors and slow-log threshold tracking for WAL syncs.
• Durable Persistence: Write-Ahead Logging (WAL) with cold-start replay and atomic HashIndex checkpointing.

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Performance Benchmarks

Measured on AMD Ryzen 9 7950X3D (Go 1.22, Windows/Linux)

Value Encryption (AES-256-GCM)

Payload Size	Encrypt Throughput	Encrypt Latency	Decrypt Throughput	Decrypt Latency
256 B	1201 MB/s	213 ns	2302 MB/s	111 ns
4 KB	2532 MB/s	1.6 µs	3713 MB/s	1.1 µs
64 KB	3072 MB/s	21.3 µs	4164 MB/s	15.7 µs
1 MB	4230 MB/s	247 µs	4930 MB/s	212 µs

Value Compression (LZ4)

Payload Size	Compress Throughput	Decompress Throughput
256 B	8.9 MB/s	1796 MB/s
4 KB	131 MB/s	2051 MB/s
64 KB	881 MB/s	2179 MB/s
1 MB	1242 MB/s	2052 MB/s

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Quick Start

Build & Run locally

# Build binary
go build -o horreum ./cmd/horreum

# Run with standard YAML configuration
./horreum --config config.yaml

Run with Docker

# Build Docker image
docker build -t horreum:latest .

# Run container
docker run -d -p 7373:7373 -p 9090:9090 --name horreum horreum:latest

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Client Examples

Horreum uses a lightweight 10-byte binary wire protocol. Ready-to-use client implementations are provided in the examples/ directory:

• Python Client
• Node.js Client
• Go Client

Python Example

from examples.client import HorreumClient

client = HorreumClient('127.0.0.1', 7373)
client.connect()

# Set key
client.set("user:1001", "Alice")

# Get key
val = client.get("user:1001")
print("User:", val.decode())

client.close()

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Documentation

For comprehensive guides and architecture details, refer to the docs/ directory:

• Getting Started Guide — Detailed setup, client usage, and Docker deployment.
• Configuration Reference — Full config.yaml and CLI flag specifications.
• Protocol Specification — 10-byte binary frame specification.
• Architecture Deep Dive — Memory layout, concurrency, and persistence design.

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License

Standard repository license applies. See AGENTS.md for project directives and code style conventions.