By installing wp-cache the testcase went down to 0.4 seconds.

 The drawback is that my counter widget is getting updated every hour instead of every reload of the webpage.

Take a peak at some nice graphs showing that I stopped the increasing loading time and got a speedup from 7.5 seconds to 0.4 seconds:

The more logical name gives date and title of the blog post instead of a cryptic number. Changing from one to another is rather simple, just change it in the wordpress settings, but there is several drawbacks:

• Referers stop working, if someone is refering to your pages they will stop working until someone updates the link
• Search engines will refer to the wrong page until the pages are indexed again and very likely the rank will drop
• Wordpress internal references will stop working, so the mainpage links will stop working. This is real stupid and I do not understand why Wordpress behaves like this.

The solution is to install the plugin  "Permalinks Moved Permanently" which fixes this problem, make sure that the webserver allows rewrite.

Links

• The plugin used Permalinks Moved Permanently
• A webpage describing howto enable mod_rewrite for Ubuntu Server.