You are checking your MySQL logs in /var/log/mysqld.log and come across an error like this:
161222 18:03:40 [ERROR] /usr/libexec/mysqld: Table './eximstats/sends' is marked as crashed and last (automatic?) repair failed
The Solution:
cd /var/lib/mysql/eximstats
myisamchk -r sends.MYI
- recovering (with sort) MyISAM-table 'sends.MYI'
Data records: 71129........