Query to get size of database tables in MB


If your hosting environment has no database monitoring, you should be able to monitor it manually once in a while or with your own shell script to prevent rapidly growing MySQL tables, because the result of large MySQL tables ( I am talking about 2 – 10 GB with millions of rows ) are often random performance issues, especially if you are using community modules with not well written MySQL queries.

This is the output of the query.

Table is marked as crashed and should be repaired

Don’t freak out if your Magento is not working and because of the following error message.

The reason of a crashed MySQL table is mostly related to a server issue. For example:

  • Any kind of hard-disk failure
  • Sudden server reboot (power outage in hosting)
  • Hard server reboot (ACPI shutdown)

In most cases you can repair the affected table with a simple repair command, which comes with MySQL.

This command looks pretty easy and safe, but keep in mind that you should always create a backup before you change anything in your database, because probably more MySQL tables are affected.

Useful Postfix Commands

If your server is configured to send emails with postfix, you should be familiar with some basic Postfix commands without any help from your sysadmin.

1. List your default and custom settings

If you have added your custom Postfix settings or set your own email aliases with virtual_alias_maps, you will find it with postconf -n.

If you want to see your Postfix default settings, just change the parameter -n to -d.

It’s a good practise to keep this output as a running configuration snapshot in a simple text file in case you have any troubles with Postfix after server reboot or software updates.

2. List the current queue and email id’s

Check your postqueue frequently to make sure all your emails were delivered correctly. If everything is okay you will see the message “Mail queue is empty”. Otherwise, you will see a list of  undelivered emails.

3. Read emails from the queue

4. Delete emails from the queue