How to change MariaDB error log from syslog to separated log file
On my.cnf, you can see the message like this.
# Error logging goes to syslog due to /etc/mysql/conf.d/mysqld_safe_syslog.cnf.
Therefore, if you want to see MariaDB error Log, then you need to check syslog.
For e.g.
$ cat /var/log/syslog | grep "mysql"
$ cat /var/log/syslog | grep "mariadb"
You can change the configuration to edit "/etc/mysql/conf.d/mysqld_safe_syslog.cnf".
$ sudo vi /etc/mysql/conf.d/mysqld_safe_syslog.cnf
[mysqld_safe]
skip_log_error
#syslog
Afterward, input the error log file on my.cnf.
$ vi /etc/mysql/my.cnf
log_error = /var/log/mysql/error.log
Restart MariaDB.
Reference.
https://mariadb.com/kb/en/mariadb/error-log/