User Spam Remover and DB Cache Reloaded Fix conflict

Yes, I can tell what this is right away. User Spam Remover expects a $wpdb to be an instance of wpdb (the WordPress database interface class) or an instance of a child class of wpdb.

The other plugin must have replaced wpdb with its own class (which isn’t of type wpdb either). What they should have done is extended wpdb if they meant to implement the same interfaces/functionality.

If you’re not a coder and that didn’t mean anything to you, don’t worry. Here’s the workaround.

If you look in user-spam-remover.php where __construct is defined (line 92 of current version), you will see:

private function __construct(wpdb $wpdb) {

Remove the ‘wpdb’ type hint. So that it looks like this:

private function __construct($wpdb) {

And that should take care of it. Providing, of course, that dbrc_wpdb is a drop-in replacement for wpdb, which presumably it is (but I don’t use it).

BTW, and this is OT, I have looked at this other plugin and the claims it is making about performance increases are fantastic.

A full-page static caching plugin like WP Super Cache or Total Cache is going to reduce page load times on the order of 100x vs. any solution like this that still hits the PHP interpreter and requires WordPress to bootstrap. The fact that somebody would even claim that is a huge red flag to me.

Simply saving database query results to disk isn’t going to have much impact on page generation times, unless you have a plugin that is doing something seriously wrong with SQL. It could even make your site slower under load because it’s adding some memory copies and reading and writing these query results from/to you web server’s disk. If you really want to cache database queries, you’re far better off just tuning your database server’s query cache than using PHP and disk to do this. But, like I said, caching full pages or even just page fragments like your sidebar (whether to memory or disk) is going to be far more effective.

Thanks for the responses. I do not want to start editing plugins myself, so have decided to drop the database caching plugin.

I too have my doubts about the performance gains of the DB caching plugin, as it also seems to me to be slowing down page serves on the two sites where I’ve tried it. I’ll stick with WP Super Cache, however.

Lastly, thanks for your nice plugin. I use it on two article sites and it surely does the job!