我们先看一下这个报错日志:InnoDB:Warning:alongsemaphorewait:--Thread140593224754944haswaitedatbtr0cur.cline528for241.00secondsthesemaphore:X-lockonRW-
我们先看一下这个报错日志:
这台机器凌晨MySQL进程崩溃,错误日志里全都是
InnoDB: Warning: a long semaphore wait
--Thread 140570431108864 has waited at btr0cur.c line 528 for 241.00 seconds the semaphore:
X-lock on RW-latch at 0x7fd9142bfcc8 created in file dict0dict.c line 1838
查看监控图(参考25日至31日)
发现spin waits和OS waits等待时间相当高,,在手册里查到了这一句话:
You can monitor the use of the adaptive hash index and the contention for its use in the SEMAPHORES section of the output of the SHOW ENGINE INNODB STATUS command. If you see many threads waiting on an RW-latch created in btr0sea.c, then it might be useful to disable adaptive hash indexing.由于自适应哈希索引造成大量的锁争用,进而堵塞很多进程,最终导致MySQL崩溃重启。
找到原因后,关闭了自适应哈希索引,观察了一天后(参考性能图1月1日),spin waits和OS waits等待时间逐渐减少。
set global innodb_adaptive_hash_index = 0;最终病因找到解决之。
参考手册:
本文出自 “贺春旸的技术专栏” 博客,请务必保留此出处

The article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.

Article discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]

Article discusses strategies for handling large datasets in MySQL, including partitioning, sharding, indexing, and query optimization.

Article discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]

The article discusses dropping tables in MySQL using the DROP TABLE statement, emphasizing precautions and risks. It highlights that the action is irreversible without backups, detailing recovery methods and potential production environment hazards.

Article discusses using foreign keys to represent relationships in databases, focusing on best practices, data integrity, and common pitfalls to avoid.

The article discusses creating indexes on JSON columns in various databases like PostgreSQL, MySQL, and MongoDB to enhance query performance. It explains the syntax and benefits of indexing specific JSON paths, and lists supported database systems.

Article discusses securing MySQL against SQL injection and brute-force attacks using prepared statements, input validation, and strong password policies.(159 characters)


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Dreamweaver CS6
Visual web development tools

WebStorm Mac version
Useful JavaScript development tools

Zend Studio 13.0.1
Powerful PHP integrated development environment

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.