Repair broken MySQL tables

From time to time this error will occur (with MySQL < 5.7), mostly because the POI table uses MyISAM as storage engine.

Mysql2::Error: Incorrect key file for table './wheelmap_production/pois.MYI'; try to repair it

To fix this, you have to run follow these steps:

1. Backup the current database

$ mysqldump -u <username> -p <database> > ~/dump.sql

2. Then shutdown the application process

$ sudo /etc/init.d/unicorn_production stop

3. Repair the tables (Run this in screen or tmux preferably)

$ mysqlcheck -u <username> -p --repair --databases db_name