https://axerzone.cn/tags/%E6%80%A7%E8%83%BD%E4%BC%98%E5%8C%96/Recent content in 性能优化 on Weiming's BlogHugo -- gohugo.iozh-cn© 2026 WeimingSat, 15 Jun 2024 00:00:00 +0000https://axerzone.cn/posts/mysql-index-optimization/Sat, 15 Jun 2024 00:00:00 +0000https://axerzone.cn/posts/mysql-index-optimization/<h1 class="relative group">MySQL 索引优化，别再全表扫描了 <div id="mysql-索引优化别再全表扫描了" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#mysql-%e7%b4%a2%e5%bc%95%e4%bc%98%e5%8c%96%e5%88%ab%e5%86%8d%e5%85%a8%e8%a1%a8%e6%89%ab%e6%8f%8f%e4%ba%86" aria-label="锚点">#</a> </span> </h1> <p>上学期数据库课的大作业，我写了个选课系统。数据量小的时候跑得飞快，一导入几万条测试数据就卡得不行。一查原因——全表扫描。那时候才真正意识到索引有多重要。</p> <h2 class="relative group">B+树——索引的底层结构 <div id="b树索引的底层结构" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#b%e6%a0%91%e7%b4%a2%e5%bc%95%e7%9a%84%e5%ba%95%e5%b1%82%e7%bb%93%e6%9e%84" aria-label="锚点">#</a> </span> </h2> <p>MySQL 的 InnoDB 引擎用 B+树组织索引。</p>