Your PHP installation appears to be missing the MySQL extension which is required by WordPress and some other PHP strangeness
I just went trough some issues with a PHP5 installation on some of our WordPress servers. To spare you of the details, why I had to do that, I simply post the solutions here (strange enough searching for these issues online gives you “trillions” of results, but no solution…).
1. Removing PHP5 and re-installing
When you are in need to remove and re-install PHP5, you should use the “–purge” parameter like; “apt-get –purge remove php5”. Now, while this seams to work and when you re-install PHP5 it strangely gives you feedback of “Not replacing deleted config file /etc/php5/apache2/php.ini” during re-installation.
In short, the re-installation does NOT install a php.ini file. While this might not be a issue for some, it was in my case. Luckily, there are some default php.ini files that one can copy. Depending on your server they might be in different places (mine were at /usr/share/php5). So, all there was to do is to copy the file with: “cp /usr/share/php5/php.ini-production /etc/php5/apache2/php.ini”.
2. Your PHP installation appears to be missing the MySQL extension which is required by WordPress
While the above might not be major issue, the message I received from our WordPress installation of “Your PHP installation appears to be missing the MySQL extension which is required by WordPress” was worrying. Nothing that I tried, re-installing PHP5, enabling modules, checking Apache and MySQL solved it. Also, searching for this online, did not help at all, since almost every entry simply tells you to re-install php5.
Ok, so how did I get it solved? After hours of hours the solution is too simple. All I had to do, was to explicitly, enable the extension in the php.ini file with:
Saved the file, restarted Apache and finally I got the MySQL parameters in the PHP Info page and all blogs worked again. One would think that the apt-get installation routine would do this automatically since I was using “apt-get install php5-mysql”, but alas as I found out the hard way, this is not so.
Hope this helps someone out there.