search
HomeDatabaseMysql TutorialLinux中MySQL 无法正常启动的解决

最近在公司做的项目中用到了MySQL数据库,系统版本是CentOS 5.1 i386。在刚安装完时,使用quot;service mysql startquot;无法正

最近在公司做的项目中用到了MySQL数据库,系统版本是CentOS 5.1 i386。

在刚安装完时,使用"service mysql start"无法正常开启。手动运行mysqld_safe程序,错误信息是"...../etc/rc.d/init.d/mysql 159:kill(xxxx) no such process"。在网上搜了一下,很多人都解决了,但是没有见到详细的讲解和错误原因的分析。我又看了一下MySQL的说明文档,发现了问题所在。此错误信息,说明mysqld_safe程序启动失败---虽然显示的是无法kill某进程,此处的kill只是为了测试指定进程是否仍然存在。

当出现错误时,你需要检查以下内容:

1、selinux是否已经关闭。

2、如果使用默认的方式安装,查看用户"mysql"是否已创建。

3、mysql配置信息中的datadir目录是否已经创建(使用此命令查看已配置的datadir:mysqld --verbose --help | grep datadir)。

4、datadir目录的所有者,是否和mysqld_safe命令行选项中的相同(默认为"mysql"用户)。

错误原因分析:

1、在使用RPM包安装完MySQL-server-xxxx.rpm之后,会看到终端中显示了上面提到的错误,MySQL开启失败。此时造成开启失败的原因,很有可能是开启了selinux,关闭selinux(具体方法请google一下),重启系统,,一般情况下,问题可以解决。刚才已在我的虚拟机中重新尝试了一次。

2、使用rpm包进行安装时,会自动创建"mysql"用户,但是在某些“可信的操作系统”中,root用户无权添加新用户,会导致错误。此时你可以使用具有添加新用户权限的用户,手动添加"mysql"帐户,密码随意设置。当你只能使用root用户时,可以在my.cnf(下面会介绍此文件)中做如下修改:

[mysqld]

user = root   #或者是其他可使用的用户名称

此处的"root"即为脚本中调用mysqld_safe程序时,命令行中指定的系统用户。

3、安装MySQL-server-xxxx.rpm之后,显示正常开启,但是修改了my.cnf(原文件为/usr/share/mysql/中的my-xxxx.cnf文件,需要选择合适的文件复制到/etc/目录中,并且改名为my.cnf)文件之后,出现错误。此时错误的原因,很有可能是因为你没有调用mysql_install_db函数,此函数负责创建mysql的基本数据库,如登录用户的信息等,以及使用my.cnf对mysql进行配置,如数据库目录(datadir),根目录(basedir)等。在当前系统中,默认datadir为/var/lib/mysql/。

4、使用rpm包安装时,mysql_install_db函数被默认的调用,但是配置信息也是默认的。当你改写了my.cnf文件之后,需要重新调用"mysql_install_db --user=mysql"命令,以按照新的配置文件对数据库进行配置。其中的"--user=mysql"选项,使创建的datadir的创建者和所有者为mysql用户(使用rpm包安装时,自动创建此用户)。如果没有为mysqld_safe指定其他用户,必须添加此选项。

参考以上的方法,MySQL无法正常启动的问题应该能够解决。对于CentOS 5.1以外的系统,没有进行测试。

linux

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How do you handle database upgrades in MySQL?How do you handle database upgrades in MySQL?Apr 30, 2025 am 12:28 AM

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

What are the different backup strategies you can use for MySQL?What are the different backup strategies you can use for MySQL?Apr 30, 2025 am 12:28 AM

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

What is MySQL clustering?What is MySQL clustering?Apr 30, 2025 am 12:28 AM

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

How do you optimize database schema design for performance in MySQL?How do you optimize database schema design for performance in MySQL?Apr 30, 2025 am 12:27 AM

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

How can you optimize MySQL performance?How can you optimize MySQL performance?Apr 30, 2025 am 12:26 AM

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi

How to use MySQL functions for data processing and calculationHow to use MySQL functions for data processing and calculationApr 29, 2025 pm 04:21 PM

MySQL functions can be used for data processing and calculation. 1. Basic usage includes string processing, date calculation and mathematical operations. 2. Advanced usage involves combining multiple functions to implement complex operations. 3. Performance optimization requires avoiding the use of functions in the WHERE clause and using GROUPBY and temporary tables.

An efficient way to batch insert data in MySQLAn efficient way to batch insert data in MySQLApr 29, 2025 pm 04:18 PM

Efficient methods for batch inserting data in MySQL include: 1. Using INSERTINTO...VALUES syntax, 2. Using LOADDATAINFILE command, 3. Using transaction processing, 4. Adjust batch size, 5. Disable indexing, 6. Using INSERTIGNORE or INSERT...ONDUPLICATEKEYUPDATE, these methods can significantly improve database operation efficiency.

Steps to add and delete fields to MySQL tablesSteps to add and delete fields to MySQL tablesApr 29, 2025 pm 04:15 PM

In MySQL, add fields using ALTERTABLEtable_nameADDCOLUMNnew_columnVARCHAR(255)AFTERexisting_column, delete fields using ALTERTABLEtable_nameDROPCOLUMNcolumn_to_drop. When adding fields, you need to specify a location to optimize query performance and data structure; before deleting fields, you need to confirm that the operation is irreversible; modifying table structure using online DDL, backup data, test environment, and low-load time periods is performance optimization and best practice.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools