How to do it...

1. Create a localized systemd configuration file:

shell> sudo mkdir -pv /etc/systemd/system/mysqld.service.d

1. Create/open the conf file:

shell> sudo vi /etc/systemd/system/mysqld.service.d/override.conf

1. Enter the following:

[Service]
LimitNOFILE=max_open_files (ex: 102400)
PIDFile=/path/to/pid/file (ex: /var/lib/mysql/mysql.pid)
Nice=nice_level (ex: -10)
Environment="LD_PRELOAD=/path/to/malloc/library" Environment="TZ=time_zone_setting"

1. Reload systemd:

shell> sudo systemctl daemon-reload

1. For temporary changes, you can reload without editing the conf file:

shell> sudo systemctl set-environment MYSQLD_OPTS="--general_log=1"
or unset using
shell> sudo systemctl unset-environment MYSQLD_OPTS

1. After modifying the systemd environment, restart the server to make the changes effective.
   Enable mysql.serviceshell> sudo systemctl, and enable mysql.service:

shell> sudo systemctl unmask mysql.service

1. Restart mysql:
   On RPM platforms:

shell> sudo systemctl restart mysqld

On Debian platforms:

shell> sudo systemctl restart mysql