I use a system for updating my packages, which is named ‘unattended-upgrades’, and which I have blogged about before Here.
This morning, that system updated my MySQL server, which is also important to this blog, because these blog entries are in fact stored in a MySQL database. The way my blog generally works, each HTTP request causes a PHP script to be executed independently on the Apache server, and the PHP extensions I have installed, include a MySQL client. This part of the PHP scripts fetches the blog content, while other parts of the scripts format it as HTML, according to the Theme which I have chosen to install some time ago.
The individual blog entries do not actually form separate files or folders on my Web-site.
Also, it is an explicit WordPress Plug-In, which tries to retrieve the already-formed HTML from my server cache, If the HTML being requested has been cached. That Plug-In is named ‘Memcached Is Your Friend‘.
The fact that my blog still displays properly, indicates that the MySQL database is operating normally. After the upgrade, the scripts also restarted this server briefly. And, the fact that this server has been restarted, does not affect the cache, nor the speed of the blog, because the ‘memcached’ daemon is a separate process which did not receive any update or restart.