cache-rs

Rust implementations of cache storage engines from Pelikan.

Crates

See design for architecture details and eviction policy comparison.

Quick Start

use segcache::{Policy, Segcache};
use std::time::Duration;

const MB: usize = 1024 * 1024;

let mut cache = Segcache::builder()
    .heap_size(64 * MB)
    .segment_size(1 * MB as i32)
    .hash_power(16)
    .eviction(Policy::S3Fifo { admission_ratio: 0.10 })
    .build()
    .expect("failed to create cache");

cache.insert(b"key", b"value", None, Duration::from_secs(300))?;
let item = cache.get(b"key").expect("not found");
assert_eq!(item.value(), b"value");
cache.delete(b"key");

Building

cargo build --workspace
cargo test --workspace

License

MIT OR Apache-2.0

lib.rs:

This crate is a Rust implementation of the Segcache storage layer.

It is a high-throughput and memory-efficient key-value store with eager expiration. Segcache uses a segment-structured design that stores data in fixed-size segments, grouping objects with nearby expiration time into the same segment, and lifting most per-object metadata into the shared segment header. This reduces object metadata by 88% compared to Memcached.

A blog post about the overall design can be found here: https://pelikan.io/2021/segcache.html

Goals:

• high-throughput item storage
• eager expiration of items
• low metadata overhead

Non-goals:

• not designed for concurrent access