root@debian:~# service mysqld start
Job for mysqld.service failed because the control process exited with error code.
See "systemctl status mysqld.service" and "journalctl -xeu mysqld.service" for details.
root@debian:~# systemctl status mysqld.service
× mysqld.service - LSB: start and stop MySQL
     Loaded: loaded (/etc/init.d/mysqld; generated)
     Active: failed (Result: exit-code) since Sun 2025-02-09 04:25:06 CST; 6s ago
       Docs: man:systemd-sysv-generator(8)
    Process: 101078 ExecStart=/etc/init.d/mysqld start (code=exited, status=1/FAILURE)
        CPU: 2.300s

Feb 09 04:25:03 debian systemd[1]: Starting mysqld.service - LSB: start and stop MySQL...
Feb 09 04:25:06 debian mysqld[101078]: Starting MySQL...The server quit without updating PID file (/www/server/data/debian.pid). ... failed!
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Control process exited, code=exited, status=1/FAILURE
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Failed with result 'exit-code'.
Feb 09 04:25:06 debian systemd[1]: Failed to start mysqld.service - LSB: start and stop MySQL.
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Consumed 2.300s CPU time.
root@debian:~# journalctl -xeu mysqld.service
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ An ExecStart= process belonging to unit mysqld.service has exited.
░░ 
░░ The process' exit code is 'exited' and its exit status is 1.
Feb 09 04:21:41 debian systemd[1]: mysqld.service: Failed with result 'exit-code'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ The unit mysqld.service has entered the 'failed' state with result 'exit-code'.
Feb 09 04:21:41 debian systemd[1]: Failed to start mysqld.service - LSB: start and stop MySQL.
░░ Subject: A start job for unit mysqld.service has failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ A start job for unit mysqld.service has finished with a failure.
░░ 
░░ The job identifier is 14279 and the job result is failed.
Feb 09 04:21:41 debian systemd[1]: mysqld.service: Consumed 2.254s CPU time.
░░ Subject: Resources consumed by unit runtime
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ The unit mysqld.service completed and consumed the indicated resources.
Feb 09 04:25:03 debian systemd[1]: Starting mysqld.service - LSB: start and stop MySQL...
░░ Subject: A start job for unit mysqld.service has begun execution
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ A start job for unit mysqld.service has begun execution.
░░ 
░░ The job identifier is 14471.
Feb 09 04:25:06 debian mysqld[101078]: Starting MySQL...The server quit without updating PID file (/www/server/data/debian.pid). ... failed!
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Control process exited, code=exited, status=1/FAILURE
░░ Subject: Unit process exited
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ An ExecStart= process belonging to unit mysqld.service has exited.
░░ 
░░ The process' exit code is 'exited' and its exit status is 1.
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Failed with result 'exit-code'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ The unit mysqld.service has entered the 'failed' state with result 'exit-code'.
Feb 09 04:25:06 debian systemd[1]: Failed to start mysqld.service - LSB: start and stop MySQL.
░░ Subject: A start job for unit mysqld.service has failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ A start job for unit mysqld.service has finished with a failure.
░░ 
░░ The job identifier is 14471 and the job result is failed.
Feb 09 04:25:06 debian systemd[1]: mysqld.service: Consumed 2.300s CPU time.
░░ Subject: Resources consumed by unit runtime
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░ 
░░ The unit mysqld.service completed and consumed the indicated resources.