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MySQL IF Statement Affect On Speed


That's the part of my query that was increasing the execution time by 10x. 

I changed it to just `table`.`start` (without the IF statement) and the query was 10x faster.

Failed to connect to socket /var/run/dbus/system_bus_socket

Error: Can't find out if NetworkManager is running: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory.
The following fixed the problem:
apt-get install dbus
(if you already have dbus installed: sudo service dbus start)
/etc/init.d/network-manager start

What caused the error?:
/etc/init.d/network restart

Could not initialize NMClient

** (process:17986): WARNING **: error: could not connect to NetworkManager

Fix: Try running with sudo.

For example: sudo nm-tool | grep DNS

Crontab Mistake

I wanted to run a script every 20 minutes, so I put this into my crontab:
20 * * * * sh

That's wrong. That only runs it once every hour 20 minutes into the hour. For example, "20,40 * * * * sh" would run it twice - 20 and 40 minutes into the hour.

To run the script every 20 minutes like I was expecting:
*/20 * * * * sh