SQL性能下降的相关内容

阿里云文档 2025-06-19

如何查看性能事件

在数据库日常运维中，您可以通过查看数据库实例中计划执行、正在执行和已执行完成的性能事件（例如异常事件、优化事件、弹性伸缩事件等），及时且全面地了解数据库的性能问题及相关的运维操作。本文介绍如何在RDS中实时查看实例的各类性能事件。

阿里云文档 2025-05-28

RDS SQL Server高性能云盘IO性能突发功能

如果您的业务波动较大，业务波峰较频繁，可以开启高性能云盘的IO性能突发功能，使云盘的IOPS不受限于最大IOPS，在业务波峰时获得更高的IO能力，满足突发业务需求。

阿里云文档 2025-05-15

如何解决在DMS中执行SQL后提示“当前SQL不满足数据库性能安全需求”

问题描述当前执行的SQL不满足数据库性能安全需求，请优化SQL并通过执行计划观察、提高SQL性能或同步元数据后重试。问题原因当查询SQL对应的执行计划为全表扫描时，DMS会自动判断当前表数据量是否大于DMS安全规则的全表扫描数据量限制。若超过，则不允许执行SQL。解决方案可通过如下方式解决此问题：通...

阿里云文档 2025-04-28

RDS高性能云盘"IO性能突发"费用减免活动

高性能云盘“IO性能突发”功能上线后，因IOPS与存储空间解耦的独特产品特性，受到广大用户的关注，RDS决定面向全网客户展开IO性能突发功能免费活动。详见RDS MySQL IO性能突发、RDS PostgreSQL IO性能突发、RDS SQL Server IO性能突发。RDS MySQL IO...

阿里云文档 2025-02-13

开发者学堂课程【MySQL 高级应用 - 索引和锁：SQL 性能下降的原因】学习笔记，与课程紧密联系，让用户快速学习知识。课程地址：https://developer.aliyun.com/learning/course/598/detail/8588SQL 性能下降的原因内容介绍一、SQL 性能下降的原因二、总结一、SQL 性能下降的原因主要是性能下降 SQL 慢、执行时间长、等待时间长不是一....

文章 2017-11-07 来自：开发者社区

在SQL中使用now()导致的性能下降(MySQL)

做数据库调优，一个简单的tip就使性能提升一大块时，被帮助的人自然是高兴而且感激，我也是满心欢喜。用所学帮助了他人，也说明还是有一技之长的，有一门能够养活自己的手艺。也算是手艺人啊。同事让我帮助优化，在slow query log里发现有两个SQL执行的次数最多，并且每次都在两秒以上。用explain看了，也未发现索引使用方面的问题。最后把怀疑的目光落在了SQL结尾处的>=now()上....

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