mvcc_cell code review

mvcc_cell code review

(Jin Qing's Column, Aug., 2024)

mvcc_cell: Software-transactional memory for Rust

Downloads: 1,475

Transactions are fully isolated and serialized:

  • Each transaction sees a fixed snapshot
  • Any concurrent commits will be prevented

Example:

rust 复制代码
let mvcc = Mvcc::new();

// Create a transactional slot
let slot = MvccCell::new(&mvcc, Box::new(0));

// Start concurrent transactions
let mut t1 = mvcc.begin();
let mut t2 = mvcc.begin();

// Uncommitted values are not visible outside the transaction
t1[&slot] = 42;
assert_eq!(t2[&slot], 0);

// First committer wins, regardless of actual modification order
t2[&slot] = 7;
assert!(t2.try_commit().is_ok());
assert!(t1.try_commit().is_err());

// Transactions always read the values that were current when
// begin() was called.
assert_eq!(mvcc.begin()[&slot], 7);

Features

  • The minimal implementation of MVCC
  • Uses 2 transaction IDs: begin ID and commit ID
    • 2 transactions can have the same begin ID
    • Commit will increase the global transaction ID
      • TxnId only increased on commit
    • Any overlap of 2 transactions is regarded as confliction
  • MvccCell stores a value with its history and pending writings
  • Snapshot isolation: reading and writing are within the snapshot
  • Non-blocking: no lock on reading and writing
  • Transaction
    • The ID of a transaction is private
    • Transaction is not Send nor Sync
  • Not two-phase commit: try_commit() will commit
  • Writing implies reading
    • Low Performance: any concurrent read or write to the same slot will fail
  • Consistency: Serializable
  • Vacuum can cleanup the history
相关推荐
该用户已不存在2 天前
Mojo vs Python vs Rust: 2025年搞AI,该学哪个?
后端·python·rust
大卫小东(Sheldon)2 天前
写了一个BBP算法的实现库,欢迎讨论
数学·rust
echoarts2 天前
Rayon Rust中的数据并行库入门教程
开发语言·其他·算法·rust
ftpeak3 天前
从零开始使用 axum-server 构建 HTTP/HTTPS 服务
网络·http·https·rust·web·web app
咸甜适中3 天前
rust语言 (1.88) 学习笔记:客户端和服务器端同在一个项目中
笔记·学习·rust
咸甜适中3 天前
rust语言 (1.88) egui (0.32.2) 学习笔记(逐行注释)(二十八)使用图片控件显示图片
笔记·学习·rust·egui
huli33203 天前
pingora_web:首款基于 Cloudflare Pingora 的企业级 Rust Web 框架
rust
Pomelo_刘金3 天前
如何优雅地抽离 Rust 子工程:以 rumqttd 为例
rust
几颗流星3 天前
Rust 常用语法速记 - 错误处理
后端·rust
向上的车轮3 天前
如何用 Rust 重写 SQLite 数据库(二):是否有市场空间?
数据库·rust·sqlite