I changed the theme and plugins used on this blog recently. Along the way I managed to slightly corrupt the settings for one of the plugins, GD Star Rating, the result being that the stars in the Top Rated Posts widget would not display. I figured out the problem: the plugin stores the path to the graphics which represent the stars, and this had incorrectly been set to an https path. Since I use a self-generated SSL certificate, the result was that browsers did not trust the connection and refused to display the graphics.
Unfortunately this path is not configured directly in the plugin options, as far I can see. I temporarily changed it to display a text rating while I worked out how to fix it.
The setting had to be in the MySQL database somewhere; and I found it. It is one value in a massive 10,000 character field called option_value, in the main options table. It seems that most of the settings for the plugin live in this single colon-separated field, even though the plugin also creates 12 tables of its own for the ratings data. Hmm, I don’t like the way this implemented. How often does this field get queried and parsed?
Still, the immediate problem was to alter the value. I ran up the MySQL interactive SQL utility and typed very carefully. This is where one false move can obliterate your WordPress install; I’m reminded of someone I knew (not me, honest) who set all his company’s customers to have the same address with a careless update missing its WHERE clause. Fortunately this is only a blog. Transactions are also good. Anyway, what could go wrong? it was a simple combination of UPDATE, REPLACE and WHERE.
It worked, the stars have returned, and I know a little bit more about the innards of WordPress and this particular plugin.