Today I restarted my CentOS 7.4 server and I found that my Mariadb server is not starting. While trying the command

systemctl start mariadb

the server showed error that Mariadb (MySql) server is unable to start try the command

systemctl status mariadb

for more information. I tried the above mentioned command and there was following error shown by above command

Can't init tc log

Aborting

So, in my case the solution was to delete the tc.log file in

/var/lib/mysql/

and then restart the server.