1. may be/usr/local/mysql/data/rekfan.pid file does not have permission to write
Workaround: Give permission, execute "chown-r mysql:mysql/var/data" "Chmod-r 755/usr/local/mysql/data" and restart mysqld!
2. The MySQL process may already exist in the process
WORKAROUND: Use the command "Ps-ef|grep mysqld" to see if there is a mysqld process, kill with "kill-9 process number" and then restart mysqld!
3. It may be the second time that MySQL is installed on the machine, with residual data affecting the start of the service.
Workaround: Go to MySQL data directory/data See, if there is mysql-bin.index, quickly delete it, it is the culprit.
4.mysql The/ETC/MY.CNF profile is used when the configuration file is not specified at startup, please open this file to see if there is a specified data directory (DATADIR) under the [Mysqld] section.
WORKAROUND: Please set this line under [mysqld]: DataDir =/usr/local/mysql/data
5.skip-federated Field Issues
Workaround: Check the/etc/my.cnf file for any skip-federated fields that have not been commented out, and if so, comment them out immediately.
6. Error log directory does not exist
Workaround: Use "Chown" "chmod" command to give MySQL owner and permissions
7.selinux, if it is a CentOS system, the default is to turn on SELinux
Workaround: Turn it off, open the/etc/selinux/config, change the selinux=enforcing to selinux=disabled, and then save the restart machine and try again.
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Mysql:the server quit without updating PID file