pid is lost. It may be that my.cnf has been modified recently. Check if there are any errors. Also check the error log and the mysql error log in the /var/log directory.
1. It may be that the /usr/local/mysql/data/mysql.pid file does not have write permission Solution: Give permission and execute "chown -R mysql:mysql /var/data" "chmod -R 755 /usr/ local/mysql/data" and then restart mysqld!
2. The mysql process may already exist in the process Solution: Use the command "ps -ef|grep mysqld" to check whether there is a mysqld process. If there is, use "kill -9 process number" to kill it, and then restart mysqld!
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
If you have encountered something similar before, you can check the error log file and find a solution on Baidu
pid is lost. It may be that my.cnf has been modified recently. Check if there are any errors. Also check the error log and the mysql error log in the /var/log directory.
1. It may be that the /usr/local/mysql/data/mysql.pid file does not have write permission
Solution: Give permission and execute "chown -R mysql:mysql /var/data" "chmod -R 755 /usr/ local/mysql/data" and then restart mysqld!
2. The mysql process may already exist in the process
Solution: Use the command "ps -ef|grep mysqld" to check whether there is a mysqld process. If there is, use "kill -9 process number" to kill it, and then restart mysqld!
You will know what the log says. The log will tell you clearly