https://answer.freetools.me/tags/%E6%95%B0%E6%8D%AE%E5%BA%93%E6%80%A7%E8%83%BD/ Recent content in 数据库性能 on Answer Hugo -- 0.152.2 zh-cn Sat, 07 Mar 2026 03:19:14 +0800 https://answer.freetools.me/%E5%88%86%E5%B8%83%E5%BC%8Fid%E7%94%9F%E6%88%90%E4%B8%BA%E4%BB%80%E4%B9%88%E4%BD%A0%E7%9A%84%E4%B8%BB%E9%94%AE%E9%80%89%E6%8B%A9%E6%AD%A3%E5%9C%A8%E6%AF%81%E6%8E%89%E6%95%B0%E6%8D%AE%E5%BA%93%E6%80%A7%E8%83%BD/ Sat, 07 Mar 2026 03:19:14 +0800 https://answer.freetools.me/%E5%88%86%E5%B8%83%E5%BC%8Fid%E7%94%9F%E6%88%90%E4%B8%BA%E4%BB%80%E4%B9%88%E4%BD%A0%E7%9A%84%E4%B8%BB%E9%94%AE%E9%80%89%E6%8B%A9%E6%AD%A3%E5%9C%A8%E6%AF%81%E6%8E%89%E6%95%B0%E6%8D%AE%E5%BA%93%E6%80%A7%E8%83%BD/ 深入分析分布式ID生成方案的权衡取舍。从UUID v4在B-tree索引中的性能问题切入，对比数据库自增ID、Snowflake算法、UUID v7、KSUID、ULID等方案的优缺点，揭示时钟回拨问题的根源与解决策略，帮助开发者根据实际需求做出正确的ID方案选择。 https://answer.freetools.me/%E6%9F%A5%E8%AF%A2%E4%BC%98%E5%8C%96%E5%99%A8%E7%9A%84%E8%87%B4%E5%91%BD%E8%AF%AF%E5%88%A4%E4%B8%BA%E4%BB%80%E4%B9%88%E6%95%B0%E6%8D%AE%E5%BA%93%E6%9C%89%E6%97%B6%E4%BC%9A%E9%80%89%E9%94%99%E6%89%A7%E8%A1%8C%E8%AE%A1%E5%88%92/ Fri, 06 Mar 2026 12:08:42 +0800 https://answer.freetools.me/%E6%9F%A5%E8%AF%A2%E4%BC%98%E5%8C%96%E5%99%A8%E7%9A%84%E8%87%B4%E5%91%BD%E8%AF%AF%E5%88%A4%E4%B8%BA%E4%BB%80%E4%B9%88%E6%95%B0%E6%8D%AE%E5%BA%93%E6%9C%89%E6%97%B6%E4%BC%9A%E9%80%89%E9%94%99%E6%89%A7%E8%A1%8C%E8%AE%A1%E5%88%92/ 从1979年System R到2023年VLDB研究，深度剖析查询优化器为何在成本估算中屡屡失手。基于微软SQL Server团队的基数估算影响研究、慕尼黑工业大学的"How Good Are Query Optimizers, Really?"等权威论文，揭示基数估计错误的指数级传播、独立性假设的现实崩塌、以及NP难问题的搜索空间困境。涵盖PostgreSQL、MySQL、Oracle等主流数据库的成本模型实现差异，以及学习型基数估计、自适应查询处理等前沿解决方案。 https://answer.freetools.me/%E4%BD%A0%E7%9A%84%E7%B4%A2%E5%BC%95%E4%B8%BA%E4%BB%80%E4%B9%88%E6%95%91%E4%B8%8D%E4%BA%86%E6%85%A2%E6%9F%A5%E8%AF%A2%E4%BB%8Eb-%E6%A0%91%E7%BB%93%E6%9E%84%E5%88%B0%E4%BC%98%E5%8C%96%E5%99%A8%E5%86%B3%E7%AD%96%E7%9A%84%E5%AE%8C%E6%95%B4%E8%A7%A3%E6%9E%90/ Wed, 04 Mar 2026 13:51:38 +0800 https://answer.freetools.me/%E4%BD%A0%E7%9A%84%E7%B4%A2%E5%BC%95%E4%B8%BA%E4%BB%80%E4%B9%88%E6%95%91%E4%B8%8D%E4%BA%86%E6%85%A2%E6%9F%A5%E8%AF%A2%E4%BB%8Eb-%E6%A0%91%E7%BB%93%E6%9E%84%E5%88%B0%E4%BC%98%E5%8C%96%E5%99%A8%E5%86%B3%E7%AD%96%E7%9A%84%E5%AE%8C%E6%95%B4%E8%A7%A3%E6%9E%90/ 从B+树结构到优化器成本模型，深度解析索引为何在关键时刻"失灵"。涵盖选择率计算、回表代价、覆盖索引、统计信息精度、深度分页陷阱、filesort原理等核心概念，提供完整的诊断方法和索引设计原则。