https://zerocoding.online/categories/%E5%90%8E%E7%AB%AF/ZeroCodingHugo 0.165.0 & FixIt v1.0.0-alpha.2-mtmrzvotzh-CNhi@zerocoding.online (ZeroCoding)hi@zerocoding.online (ZeroCoding)Thu, 30 Jul 2026 00:00:00 +0800https://zerocoding.online/posts/idempotency-design/Thu, 30 Jul 2026 00:00:00 +0800hi@zerocoding.online (ZeroCoding)https://zerocoding.online/posts/idempotency-design/后端<p>幂等性是分布式系统的老问题，却是高并发场景下最容易踩坑的地方。核心诉求只有一个：<strong>同一个操作执行多次，结果和只执行一次一致</strong>。</p> <h2 class="heading-element" id="常见落地手段"><span>常见落地手段</span> <a href="#%e5%b8%b8%e8%a7%81%e8%90%bd%e5%9c%b0%e6%89%8b%e6%ae%b5" class="heading-mark"><svg class="octicon octicon-link" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="m7.775 3.275 1.25-1.25a3.5 3.5 0 1 1 4.95 4.95l-2.5 2.5a3.5 3.5 0 0 1-4.95 0 .751.751 0 0 1 .018-1.042.751.751 0 0 1 1.042-.018 1.998 1.998 0 0 0 2.83 0l2.5-2.5a2.002 2.002 0 0 0-2.83-2.83l-1.25 1.25a.751.751 0 0 1-1.042-.018.751.751 0 0 1-.018-1.042Zm-4.69 9.64a1.998 1.998 0 0 0 2.83 0l1.25-1.25a.751.751 0 0 1 1.042.018.751.751 0 0 1 .018 1.042l-1.25 1.25a3.5 3.5 0 1 1-4.95-4.95l2.5-2.5a3.5 3.5 0 0 1 4.95 0 .751.751 0 0 1-.018 1.042.751.751 0 0 1-1.042.018 1.998 1.998 0 0 0-2.83 0l-2.5 2.5a1.998 1.998 0 0 0 0 2.83Z"></path></svg></a> </h2><ol> <li><strong>数据库唯一约束</strong>：最可靠，通过唯一索引天然去重，适合「创建」类操作。</li> <li><strong>状态机</strong>：把业务状态流转设计成幂等的，重复请求自然被挡在状态判断之外。</li> <li><strong>Token / 去重表</strong>：请求先拿 Token，消费一次即失效，适合「提交」类操作。</li> <li><strong>分布式锁</strong>：保证同一时刻只有一个请求在处理，但要处理好锁的粒度与超时。</li> </ol> <h2 class="heading-element" id="取舍"><span>取舍</span> <a href="#%e5%8f%96%e8%88%8d" class="heading-mark"><svg class="octicon octicon-link" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="m7.775 3.275 1.25-1.25a3.5 3.5 0 1 1 4.95 4.95l-2.5 2.5a3.5 3.5 0 0 1-4.95 0 .751.751 0 0 1 .018-1.042.751.751 0 0 1 1.042-.018 1.998 1.998 0 0 0 2.83 0l2.5-2.5a2.002 2.002 0 0 0-2.83-2.83l-1.25 1.25a.751.751 0 0 1-1.042-.018.751.751 0 0 1-.018-1.042Zm-4.69 9.64a1.998 1.998 0 0 0 2.83 0l1.25-1.25a.751.751 0 0 1 1.042.018.751.751 0 0 1 .018 1.042l-1.25 1.25a3.5 3.5 0 1 1-4.95-4.95l2.5-2.5a3.5 3.5 0 0 1 4.95 0 .751.751 0 0 1-.018 1.042.751.751 0 0 1-1.042.018 1.998 1.998 0 0 0-2.83 0l-2.5 2.5a1.998 1.998 0 0 0 0 2.83Z"></path></svg></a> </h2><p>没有银弹。唯一约束最稳但局限性强，锁最灵活但引入复杂度。实际项目里往往是组合使用，按业务语义选择最合适的那一层。</p>https://zerocoding.online/posts/redis-ha/Sun, 12 Jul 2026 00:00:00 +0800hi@zerocoding.online (ZeroCoding)https://zerocoding.online/posts/redis-ha/后端<p>Redis 的高可用，最常用的两条路是哨兵（Sentinel）和集群（Cluster）。选型之前，先想清楚自己的真实需求。</p> <h2 class="heading-element" id="哨兵sentinel"><span>哨兵（Sentinel）</span> <a href="#%e5%93%a8%e5%85%b5sentinel" class="heading-mark"><svg class="octicon octicon-link" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path d="m7.775 3.275 1.25-1.25a3.5 3.5 0 1 1 4.95 4.95l-2.5 2.5a3.5 3.5 0 0 1-4.95 0 .751.751 0 0 1 .018-1.042.751.751 0 0 1 1.042-.018 1.998 1.998 0 0 0 2.83 0l2.5-2.5a2.002 2.002 0 0 0-2.83-2.83l-1.25 1.25a.751.751 0 0 1-1.042-.018.751.751 0 0 1-.018-1.042Zm-4.69 9.64a1.998 1.998 0 0 0 2.83 0l1.25-1.25a.751.751 0 0 1 1.042.018.751.751 0 0 1 .018 1.042l-1.25 1.25a3.5 3.5 0 1 1-4.95-4.95l2.5-2.5a3.5 3.5 0 0 1 4.95 0 .751.751 0 0 1-.018 1.042.751.751 0 0 1-1.042.018 1.998 1.998 0 0 0-2.83 0l-2.5 2.5a1.998 1.998 0 0 0 0 2.83Z"></path></svg></a> </h2><p>主从 + 哨兵监控，主挂自动切换。<strong>适合数据量不大、但对可用性有要求的场景</strong>。优点是简单、兼容性好，缺点是数据集中在一台主节点上，受内存上限制约。</p>